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We analyze the operation of the hot-electron FET bolometers with the graphene channels (GCs) and the gate barrier layers. Such bolometers use the thermionic emission of the hot electrons heated by incident-modulated THz radiation. The hot electrons transfer from the GC into the metal gate. As the THz detectors, these bolometers can operate at room temperature. We show that the response and ultimate modulation frequency of the GC-FET bolometers are determined by the efficiency of the hot-electron energy transfer to the lattice and the GC side contacts due to the 2DEG lateral thermal conductance. The dependences of these mechanisms on the band structure and geometrical parameters open the way for the GC-FET bolometers optimization, in particular, for the enhancement of the maximum modulation frequency. [ABSTRACT FROM AUTHOR]

We present a method by which the direct detection effect in superconducting hot-electron bolometer mixers can be analytically accounted for with sufficient practical accuracy. This is achieved by means of the advanced uniform, non-linear two-temperature model that considers the effective temperatures of electrons and phonons alongside established material parameters. We demonstrate the efficacy of this approach for the ex situ correction of the radiance of the emission line of atomic oxygen under conditions when the direct detection causes a 30% error in the line magnitude. The correction was applied to data collected by a balloon-borne heterodyne receiver operating in the upper atmosphere of Earth. The corrected line shape and magnitude are in reasonable agreement with the predictions of atmospheric radiation transfer models. [ABSTRACT FROM AUTHOR]

We report on efforts to improve the speed of low-G far-infrared transition-edged-sensed bolometers. We use a fabrication process that does not require any dry etch steps to reduce heat capacity on the suspended device and measure a reduction in the detector time constant. However, we also measure an increase in the temperature-normalized thermal conductance (G) and a corresponding increase in the noise-equivalent power (NEP). We employ a new near-IR photon-noise technique using a near-IR laser to calibrate the frequency-domain multiplexed AC system and compare the results to a well-understood DC circuit. We measure an NEP white noise level of 0.8 aW/rtHz with a 1/f knee below 0.1 Hz and a time constant of 3.2 ms. [ABSTRACT FROM AUTHOR]

In this work, we propose a magnetic bolometer to be employed in the search of primordial B-modes in the CMB. These magnetic bolometers are an adaptation of the well-known metallic magnetic calorimeters used in particle physics. They rely on the magnetization dependence on temperature of alloys such as Au:Er and Ag:Er. In addition to the low intrinsic noise a magnetic bolometer of this nature offers, the broad and smooth temperature-dependent magnetization of metallic magnetic sensors ultimately translates to a high dynamic range and straightforward calibration. Their intrinsic noise equivalent power (NEP) is estimated to be in the range of 10–100 aW/ (Hz) . We outline here a workable design for such a detector utilizing an antenna-coupled approach and present the simulated power transfer ratio that was attained; the detector's performance is discussed by combining this result with its responsivity. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) non-layered materials in many aspects differ from their layered counterparts, and the exploration of their physical properties has produced many intriguing findings. However, due to challenges in applying existing experimental techniques to such nanoscale samples, their thermal properties have remained largely uncharacterized, hindering further exploration and device application using this promising material system. Here, we demonstrate an experimental study of thermal conduction in β -In2S3, a typical non-layered 2D material, using a resonant nanoelectromechanical systems (NEMS) platform. We devise a new two-degrees-of-freedom technique, more responsive and sensitive than Raman spectroscopy, to simultaneously determine both the thermal conductivity to be 3.7 W m−1 K−1 and its interfacial thermal conductance with SiO2 as 6.4 MW m−2 K−1. Leveraging such unique thermal properties, we further demonstrate a record-high power-to-frequency responsivity of −447 ppm/μW in β -In2S3 NEMS sensors, the best among drumhead NEMS-based bolometers. Our findings offer an effective approach for studying thermal properties and exploring potential thermal applications of 2D non-layered materials. [ABSTRACT FROM AUTHOR]

The infra-red video bolometer (IRVB) is a diagnostic equipped with an infra-red camera that measures the total radiated power in thousands of lines of sight within a large field of view. Recently validated in MAST-U [Fderici et al., Rev. Sci. Instrum. 94, 033502 (2023)], it offers a high spatial resolution map of the radiated power in the divertor region, where large gradients are expected. The IRVB's sensing element comprises a thin layer of high Z absorbing material, typically platinum, usually coated with carbon to reduce reflections [Peterson et al., Rev. Sci. Instrum. 79, 10E301 (2008)].Here, the possibility of using a relatively inert material such as titanium, is explored that can be produced in layers up to 1 μm compared to 2.5 μm for Pt and then coat it with Pt of the desired thickness (0.3 μm per side here) and carbon. This leads to a higher temperature signal (about 3 times) and better spatial resolution (about 4 times), resulting in higher accuracy in the measured power [Peterson et al., Rev. Sci. Instrum. 79, 10E301 (2008)]. This assembly is also expected to improve foil uniformity, as the Pt layer is obtained via deposition rather than mechanical processes [Mukai et al., Rev. Sci. Instrum. 87, 2014 (2016)].Given its multi-material composition, measuring the thermal properties of the foil assembly is vital. Various methods using a calibrated laser as a heat source have been developed, analyzing the temperature profile shape [Sano et al., Plasma and Fusion Res. 7, 2405039 (2012)] and [Mukai et al., Rev. Sci. Instrum. 89, 10E114 (2018)] or fitting the calculated laser power for different intensities and frequencies [Fderici et al., Rev. Sci. Instrum. 94, 033502 (2023)]. Here, a simpler approach is presented, which relies on analyzing the separate components of the foil heat equation for a single laser exposure in a given area. This can then be iterated over the entire foil to capture local deviations. [ABSTRACT FROM AUTHOR]

Power exhaust is one of the central challenges in magnetically confined fusion plasmas. Radiative detachment can be employed to reduce particle and heat fluxes to the divertor target, mitigating divertor damage and erosion. However, accomplishing this for a non-axisymmetric machine such as Wendelstein 7-X is a non-trivial task because of the complex role of transport and plasma-wall interaction in a three-dimensional magnetic field topology. We introduce a new bolometer camera design that can be easily installed in multiple toroidal locations and adapted to the required geometry, providing additional spatial coverage. This can be used to locally enhance tomographic capabilities or to resolve spatial variations of the plasma emissivity. By including these non-uniformities in the total radiated power estimate, global power balance measurements can be improved. We model each bolometer camera using ray tracing. We then analyze the forward-modeled detector response to several physically motivated synthetic emission phantoms with respect to its capability to quantify the local average emissivity. The results prove this concept as a promising asset for the investigation of poloidal and toroidal radiated power asymmetries in Wendelstein 7-X. The first CBC prototypes have undergone development and installation for the next experimental campaign. [ABSTRACT FROM AUTHOR]

As part of its roadmap to developing commercial fusion plants, Tokamak Energy Ltd. operates the high field spherical tokamak ST40. Studies on this device will help to expand the high field spherical tokamak physics basis by characterizing confinement and the fusion triple product. In support of this, bolometers and broadband and x-ray sensitive diodes can provide information on key energy loss mechanisms of the plasma. These mechanisms include core magnetohydrodynamic activity that deteriorates confinement, such as sawtooth crashes that can be used to characterize relaxations in the q-profile. In addition, combinations of these diagnostics can be used to infer the total radiated power losses and plasma composition. Here, we present results from a new, midplane, tangential, Be-filtered diode with 16 channels spanning the radial extent of the plasma. The system is shown to resolve magnetohydrodynamic instabilities (up to 100 kHz) and be able to provide radiation profiles through tomography. The tomographic inversion routine is compared against other diagnostics on ST40 and provides emissivity measurements across a variety of operating scenarios. Finally, we look ahead to implementing multiple soft x-ray cameras on ST40 and the improvements this will have on the diagnostic capabilities. [ABSTRACT FROM AUTHOR]

Over the past few decades, perovskite manganese oxide La x (CaSr) 1- x MnO 3 has presented new opportunities for uncooled infrared bolometers due to its exceptional electrical transport performance. In this study, La 0.67 Ca 0.25 Sr 0.08 MnO 3 (LCSMO) ceramics were prepared at different sintering temperatures (T s , T s = 1450, 1470, 1490, 1510, 1530 °C) by changing the previous sol-gel preparation process parameters. The research results indicated that the tolerance factor (τ) of the ceramics is τ = 0.935, and all ceramics exhibit a Pnma space group perovskite structure with excellent crystallinity. LCSMO ceramics exhibit good crystal quality and higher room-temperature TCR (14.58 % K−1) at T s = 1510 °C. As T s increases, the grain size, Mn–O bond length (d Mn-O), Mn– O –Mn bond angle (θ Mn-O-Mn) and cell volume (V) of ceramics have a slight affected. The decrease of grain boundary scattering, electron-electron scattering, and strong coupling between electrons, so the peak resistivity value of all sintered samples firstly decreases and then increases with the increase in T s , which effectively yields ceramics with high TCR. The peak TCR value (TCR max) increased from 8.38 % K−1 (T s = 1450 °C) at 296.91 K to 14.58 % K−1 (T s = 1510 °C) at 298.18 K. On the same component, the TCR max was increased by 42 % from 8.38 % K−1 to 14.58 % K−1 at T s = 1450 °C–1510 °C. The high room-temperature TCR of LCSMO is expected to be used in advanced uncooled infrared bolometers, providing a basis for studying the influence of T s on the electrical transport performance of ceramics. [ABSTRACT FROM AUTHOR]

We study the statistical distributions of the output signals of a superconducting hot-electron bolometer (HEB) detector exposed to weak photon pulses of 1 THz (terahertz) frequency. Pulses with variable photon numbers were generated through strongly non-degenerate parametric downconversion (PDC) in a LiNbO3 crystal at 4.8 K. Fundamental differences in histograms are found between two PDC pumping modes, with pulse widths of 28 ps and 10 ns. HEB response to a picosecond THz pulse was detected in the form of a single elementary electrical pulse (SEP), with the average amplitude proportional to radiation intensity and dispersion relative to the bolometer's dark current. HEB responses to extremely weak radiation intensities have been recorded using nanosecond pulsed illumination. We found that nanosecond histograms are asymmetrical and broaden as radiation intensity increases, indicating that the nanosecond response consists of several SEPs. Poisson–Gauss approximation of histograms indicates that not only the average number of SEPs increase but also the average amplitude of a SEP increases with increasing power of incident THz radiation. [ABSTRACT FROM AUTHOR]

Here, we present a novel spectroscopy approach to investigate impurity transport by analyzing line-radiation following high-n Rydberg transitions. While high-n Rydberg states of impurity ions are unlikely to be populated via impact excitation, they can be accessed by charge exchange (CX) reactions along the neutral beams in high-temperature plasmas. Hence, localized radiation of highly ionized impurities, free of passive contributions, can be observed at multiple wavelengths in the visible range. For the analysis and modeling of the observed Rydberg transitions, a technique for calculating effective emission coefficients is presented that can well reproduce the energy dependence seen in datasets available on the OPEN-ADAS database. By using the rate coefficients and comparing modeling results with the new high-n Rydberg CX measurements, impurity transport coefficients are determined with well-documented 2σ confidence intervals for the first time. This demonstrates that high-n Rydberg spectroscopy provides important constraints on the determination of impurity transport coefficients. By additionally considering Bolometer measurements, which provide constraints on the overall impurity emissivity and, therefore, impurity densities, error bars can be reduced even further. [ABSTRACT FROM AUTHOR]

Due to the increasing demands for active plasma control operations, in situ diagnostics are highly sought after. Tungsten plasma-facing components have been utilized in the Korea Superconducting Tokamak Advanced Research (KSTAR) lower divertor since the 2023 campaign. Plasma radiation is a key parameter for plasma control, especially in radiation front control experiments. Therefore, the KSTAR infra-red video bolometer (IRVB) needs to be reconfigured into an in situ data streaming diagnostic. This requires comprehensive changes in both infra-red camera control and data analysis compared to the previous system. To ensure the stability of the reconfigured system, functional parts are grouped and separated into individual processes to protect camera acquisitions from errors in other processes. In addition, to enhance the speed of data streaming analysis, the analysis code has been optimized and converted into graphics processing unit (GPU) code. Besides the data streaming analysis, the system is also designed to support post-shot analysis with the entire frame data for the same shot to address frame drop issues encountered during data streaming. Radiation front control experiments with N2 gas seeding are successful results of the data streaming IRVB for its commissioning. This paper focuses on the development of the data streaming IRVB system. [ABSTRACT FROM AUTHOR]

A new type of large area sensor for infrared imaging bolometers has been developed. It replaces the thin and fragile free-standing metal foils, which typically have been used, with a multi-layer coated sapphire (or diamond) substrate. Sapphire is transparent to mid-infrared wavelengths, is robust against transients, and can be thick enough to even be the vacuum window. The primary radiation absorber is still a thin deposited metal layer, but now it is partially insulated from the supporting sapphire substrate by a black (carbon-based) layer, which also acts as a blackbody remitter. Test results indicate 6× more noise equivalent power density (estimated NEPD = 23 W/m2 at 5 ms camera exposure time, foil temperature decay time 60 ms) for a 2 μm gold-coated sapphire disk compared to estimated NEP = 4 W/m2 at 1.8 ms exposure time, with foil decay time 420 ms, for a nominal 2.5 μm thick platinum-free-standing foil. [ABSTRACT FROM AUTHOR]

We describe a novel ultrahigh vacuum state-to-state molecule/surface scattering apparatus with quantum state preparation of the incident molecular beam and angle-resolved quantum state detection of the scattered molecules. State-resolved detection is accomplished using a tunable mid-infrared laser source combined with a cryogenic bolometer detector and is applicable to any molecule with an infrared-active vibrational transition. Results on rotationally inelastic scattering of CH4 methane from a Ni(111) surface and NiO(111)/Ni(111) oxide film, obtained by the new apparatus, are presented. Molecules scattering from the oxidized surface, compared to those scattering from the bare nickel surface, are more highly excited rotationally and scatter into a broader distribution of angles. The internal alignment of molecular rotation is in addition found to be stronger in molecules scattering from the bare surface. Furthermore, the maxima of the state-resolved angular distributions shift toward and away from surface normal with increasing rotational quantum number J for the oxidized and bare surface, respectively. Finally, the rotational state populations produced in scattering from the oxidized surface are well-described by a Boltzmann distribution, while those produced in scattering from the bare surface exhibit large deviations from their best-fit Boltzmann distributions. These results point toward a marked enhancement in molecule–surface collisional energy exchange induced by oxidation of the nickel surface. [ABSTRACT FROM AUTHOR]

To control and optimize the power of the SPARC tokamak, we require information on the total radiated power of the plasma and its 2D and 3D spatial distribution. The SPARC bolometry diagnostic is being designed and built to measure the radiated power for controlling power balance, investigating the dissipation capabilities of various divertor concepts, and measuring the efficacy of the disruption thermal load mitigation. Proven resistive bolometer sensor technology will be used, with 248 lines of sight integrated into pinhole cameras in 20 different locations. This diversity of views will allow the bolometers to view the core, divertor, and particularly X-points of the plasma with high resolution. 14 of these camera locations are dedicated to 2D equilibrium radiated power, while the remaining six locations are designed to measure 3D radiated energy during disruptions. The bolometer sensor holders, pinhole camera boxes, and cabling have been designed to survive the high neutron flux (but low fluence) and up to 400 °C temperatures seen during operation and vacuum bake. The resistive bolometer sensors use Au absorbers with an Al heat conduction layer and C anti-reflective layer. These sensor chips are wire-bonded to an AlN circuit board, both of which are held inside a custom AlN and stainless steel bolometer holder. Design and optimization of the pinhole camera lines of sight are performed using Cherab. This work details the current state of the design of the SPARC bolometry diagnostic and its interfaces, as well as ongoing work to validate the design. [ABSTRACT FROM AUTHOR]

Following successful campaigns on the compact high field spherical tokamak ST40, resistive gold foil bolometers have now been installed to measure the radiated power profile. Positioned on the midplane, two bolometer cameras offer perspectives of the horizontal and vertical planes, while the third camera, situated above the midplane, provides a vertical view of the top divertor plates, including the X-point and the strike points. These cameras use a commercial off-the-shelf data acquisition platform with modules specifically designed for bolometers in a Wheatstone bridge configuration, providing both phase sensitive detection and in situ calibration. This paper presents an overview of the design and functionality of all three cameras and the commissioning of the horizontal plane camera. The commissioning of the horizontal camera shows data from a range of plasma pulses, presenting a positive correlation between the relative profiles measured from the bolometer camera and an absolute extreme ultraviolet diode camera viewing along similar lines of sight. [ABSTRACT FROM AUTHOR]

The detachment cliff is a bifurcative transition to partial detachment recently discovered at the DIII-D tokamak (McLean et al 2015 J. Nucl. Mater. 463 533–6). This work presents a database analysis of target parameters in L-mode and H-mode discharges to search for a detachment cliff at ASDEX Upgrade (AUG). Most of the transitions from attached to partially detached divertor conditions observed in H- and L-mode discharges in AUG show bifurcative-like characteristics that are consistent with the properties of the detachment cliff if the B × ∇ B drift is directed towards the active X-point. In the operational space of power and density, the bifurcative transitions identified during an L-mode discharge occur at injected power and density higher than a threshold value ( P tot > 0.7 MW and n e > 1.6 × 10 19 m−3, respectively). Furthermore, the temperatures at which the transitions start are found to be insensitive to the injected impurity, the injected power and the value of the upstream density. Finally, the study of the evolution of the target parameters, of the intensity of the D α line and of specific manometers and bolometer lines of sights shows that the physical process underlying the detachment cliff and the self-sustained divertor oscillations (Heinrich 2020 Nucl. Fusion 60 076013) might be the same. [ABSTRACT FROM AUTHOR]

We present a method for precise monitoring of the loop gain of transition edge sensors (TES) under electrothermal feedback. The measurement is implemented on the ICE DfMux electronics and operates simultaneously with Digital Active Nulling (DAN). It uses one additional bias sinusoid per TES and does not require any additional readout channels. The loop gain monitor is being implemented on the Simons Array and is an integral part of the baseline calibration strategy for the upcoming LiteBIRD satellite. [ABSTRACT FROM AUTHOR]

The B-BOP detector is composed of polarization sensitive bolometer arrays in the 70–350 µm spectral range with a goal sensitivity around one attoWatt/sqrt (Hz). A polarized infrared calibration set-up is required to evaluate its performances. The calibration source is based on 6-ring-shaped, concentric blackbody-like emitters that can be individually controlled. The total emitting surface is therefore tunable from 9 up to 1200 mm2. The temperature is tunable from 1 to 40 K without disturbing the dilution cryostat and the working temperature of the detector arrays. The present paper describes the source, the rotating polarizer at low temperature, the modulation means, and the complete optical tube leading polarized infrared photons for characterizing detectors down to femtowatt level. Details of the design and realization are discussed. [ABSTRACT FROM AUTHOR]

Cosmic microwave background (CMB) experiments have deployed focal planes with O (10 4) transition edge sensor (TES) bolometers cooled to sub-Kelvin temperatures by multiplexing the readout of many TES channels onto a single pair of wires. Digital Frequency-domain Multiplexing (DfMux) is a multiplexing technique used in many CMB polarization experiments, such as the Simons Array, SPT-3 G, and EBEX. The DfMux system studied here uses LC filters with resonant frequencies ranging from 1.5 to 4.5 MHz connected to an array of TESs. Each detector has an amplitude-modulated carrier tone at the resonant frequency of its accompanying LC resonator. The signal is recovered via quadrature demodulation where the in-phase (I) component of the demodulated current is in phase with the complex admittance of the circuit and the quadrature (Q) component is orthogonal to I. Observed excess current noise in the Q component is consistent with fluctuations in the resonant frequency. This noise has been shown to be non-orthogonal to the phase of the detector's responsivity. We present a detailed analysis of the phase of responsivity of the TES and noise sources in our DfMux readout system. Further, we investigate how modifications to the TES operating resistance and bias frequency can affect the phase of noise relative to the phase of the detector responsivity, using data from Simons Array to evaluate our predictions. We find that both the phase of responsivity and phase of noise are functions of the two tuning parameters, which can be purposefully selected to maximize signal-to-noise (SNR) ratio. [ABSTRACT FROM AUTHOR]

POLARBEAR-2b (PB-2b) is the second receiver in the Simons Array, a cosmic microwave background (CMB) polarization experiment. The Simons Array uses dichroic polarization sensitive lenslet-coupled sinuous antennas and transition-edge sensor (TES) bolometers made of superconducting films. These bolometers are read out with frequency multiplexing electronics. PB-2b contains ∼ 7500 detectors in two bands at 90 and 150 GHz with arcminute resolution. The polarization of these detectors is modulated by a cryogenic continuously rotating half-wave plate. PB-2b was installed on its telescope in 2022 in the Atacama Desert at an altitude of 5.2 km. This paper will detail initial readout commissioning, test of a new loopgain monitoring method, and focusing the optics. Work is ongoing to commission the remaining ambient temperature readout electronics, measure detector time constants, and observe with the cryogenic half-wave plate spinning [ABSTRACT FROM AUTHOR]

Transition-edge sensor (TES) bolometers are broadly used for background-limited astrophysical measurements from the far-infrared to mm-waves. Many planned future instruments require increasingly large detector arrays, but their scalability is limited by their cryogenic readout electronics. Microwave SQUID multiplexing offers a highly capable scaling solution through the use of inherently broadband circuitry, enabling readout of hundreds to thousands of channels per microwave line. As with any multiplexing technique, the channelization mechanism gives rise to electrical crosstalk which must be understood and controlled so as to not degrade the instrument sensitivity. Here, we explore implications relevant for TES bolometer array applications, focusing in particular on upcoming mm-wave observatories such as the Simons Observatory and AliCPT. We model the relative contributions of the various underlying crosstalk mechanisms, evaluate the difference between fixed tone and tone-tracking readout systems, and discuss ways in which crosstalk nonlinearity will complicate on-sky measurements. [ABSTRACT FROM AUTHOR]

The 2020 decadal review recognized the measurement of the polarization of the cosmic microwave background (CMB) to be a top priority for the decade. CMB experiments including POLARBEAR2/Simons Array, Atacama Cosmology Telescope/Advanced-ACT, SPT-3G, the Simons Observatory, and CMB-S4 have or will use transition edge sensor (TES) bolometer fabricated with Aluminum doped with Manganese (AlMn). AlMn is a popular material choice as the superconducting transition temperature ( T c ) and normal resistance ( R n ) of the TES can be tuned with Mn concentration, geometric patterning, film thickness, and thermal annealing. In addition the conductivity is appropriate for both time division multiplexing and frequency division multiplexing that require 10 m Ω and 1 Ω sensors respectively. In this paper we present work on the ability to tune the T c of a film based on its time and temperature thermal tuning profile combined with room temperature monitoring of film resistivity. Such control allows for the fabrication of a wide range of TES parameters from a single AlMn concentration. Scanning electron microscope (SEM) imaging shows that the AlMn film's grain boundaries are changed by thermal annealing making the film more conductive and raising its superconducting transition temperatures, and that at high enough temperatures will eventually recover the T c of bulk Al. We find that baking films at ∼ 200 ∘ C for tens of minutes yields a T c that is suitable for 100 mK base temperature experiments and we present on the thermal tune profiles of several different thicknesses of AlMn. [ABSTRACT FROM AUTHOR]

The Simons Observatory (SO) is a cosmic microwave background instrumentation suite in the Atacama Desert of Chile. More than 65,000 polarization-sensitive transition-edge sensor (TES) bolometers will be fielded in the frequency range spanning 27 to 280 GHz, with three separate dichroic designs. The mid-frequency 90/150 GHz and ultra-high-frequency 220/280 GHz detector arrays, fabricated at NIST, account for 39 of 49 total detector modules and implement the feedhorn-fed orthomode transducer-coupled TES bolometer architecture. A robust production-level fabrication framework for these detector arrays and the monolithic DC/RF routing wafers has been developed, which includes single device prototyping, process monitoring techniques, in-process metrology, and cryogenic measurements of critical film properties. Application of this framework has resulted in timely delivery of nearly 100 total superconducting focal plane components to SO with 88 % of detector wafers meeting nominal criteria for integration into a detector module: a channel yield > 95 % and T c in the targeted range. [ABSTRACT FROM AUTHOR]

Characterization of the magnetic fields at different scales in the Universe is a new frontier for submillimeter astronomy. Polarimetric measurements between 50 and 500 µm are the golden path for this research. We develop, in the prospect of space observatories, all-silicon 50 mK bolometer arrays with polarimetric capabilities in the pixel. Here, we present the first results of the new detectors: performances of thermal sensors, optical absorption and polarimetry. [ABSTRACT FROM AUTHOR]

Time-division multiplexing is the readout architecture of choice for many ground and space experiments, as it is a very mature technology with proven outstanding low-frequency noise stability, which represents a central challenge in multiplexing. Once fully populated, each of the two BICEP Array high-frequency receivers, observing at 150 GHz and 220/270 GHz, will have 7776 TES detectors tiled on the focal plane. The constraints set by these two receivers required a redesign of the warm readout electronics. The new version of the standard multichannel electronics, developed and built at the University of British Columbia, is presented here for the first time. BICEP Array operates time-division multiplexing readout technology to the limits of its capabilities in terms of multiplexing rate, noise and cross talk, and applies them in rigorously demanding scientific application requiring extreme noise performance and systematic error control. Future experiments like CMB-S4 plan to use TES bolometers with time-division/SQUID-based readout for an even larger number of detectors. [ABSTRACT FROM AUTHOR]

We report the results of radioactivity assays and heat leak calculations for a range of common cryogenic materials, considered for use in the QUEST-DMC superfluid 3 He dark matter detector. The bolometer, instrumented with nanomechanical resonators, will be sensitive to energy deposits from dark matter interactions. Events from radioactive decays and cosmic rays constitute a significant background and must be precisely modelled, using a combination of material screening and Monte Carlo simulations. However, the results presented here are of wider interest for experiments and quantum devices sensitive to minute heat leaks and spurious events, thus we present heat leak per unit mass or surface area for every material studied. This can inform material choices for other experiments, especially if underground operation is considered – where the radiogenic backgrounds will dominate even at shallow depths. [ABSTRACT FROM AUTHOR]

CUPID is a next-generation tonne-scale bolometric neutrinoless double beta decay experiment that will probe the Majorana nature of neutrinos and discover lepton number violation in case of observation of this singular process. CUPID will be built on experience, expertise and lessons learned in CUORE and will be installed in the current CUORE infra-structure in the Gran Sasso underground laboratory. The CUPID detector technology, successfully tested in the CUPID-Mo experiment, is based on scintillating bolometers of Li2MoO4 enriched in the isotope of interest 100Mo. In order to achieve its ambitious science goals, the CUPID collaboration aims to reduce the backgrounds in the region of interest by a factor 100 with respect to CUORE. This performance will be achieved by introducing the high efficient α/β discrimination demonstrated by the CUPID-0 and CUPID-Mo experiments, and using a high transition energy double beta decay nucleus such as 100Mo to minimize the impact of the gamma background. CUPID will consist of about 1500 hybrid heat-light detectors for a total isotope mass of 250 kg. The CUPID scientific reach is supported by a detailed and safe background model based on CUORE, CUPID-Mo and CUPID-0 results. The required performances have already been demonstrated and will be presented.

We have studied THz heterodyne detection in sub-micrometer MgB2 hot electron bolometer (HEB) mixers based on superconducting MgB2 films of ∼ 5 nm (HEB-A), corresponding to a critical temperature (Tc) of 33.9 K, and ∼ 7 nm (HEB-B), corresponding to a T c of 38.4 K. We have measured a double sideband (DSB) receiver noise temperature of 2590 K for HEB-A and 2160 K for HEB-B at 1.6 THz and 5 K. By correcting for optical losses, both HEBs show receiver noise temperatures of ∼1600 K referenced to the front of anti-reflection (AR)-coated Si lenses. An intermediate frequency (IF) noise bandwidth of 11 GHz has been measured for both devices. The required local oscillator (LO) power is about 13 μW for both HEBs. We have also measured a DSB receiver noise temperature of 3290 K at 2.5 THz and 5 K but with an AR-coated lens optimized for 1.6 THz. Besides, we have observed a step-like structure in current voltage (IV) curves, which becomes weaker when the LO power increases and observable only in their differential resistance. Such a correlated structure appears also in the receiver output power as a function of voltage, which is likely due to electronic inhomogeneities intrinsic to the variations in the thickness of the MgB2 films. Different behavior in the IV curves around the low bias voltages, pumped with the same LO power at 1.6 and 5.3 THz, was observed for HEB-B, suggesting the presence of a high-energy σ-gap in the MgB2 film. [ABSTRACT FROM AUTHOR]

This work comprehensively discusses the utilization of a metal-multiwalled carbon nanotube (CNT) nanocomposite of gold (Au)/CNT for uncooled bolometric application synthesized by a simple rapid green synthesis technique. Enhanced light–matter interaction with the visible (532 nm) and near-infrared (1064 nm) radiations in the nanocomposite is utilized for achieving improved bolometric response at room temperature (RT, ∼300 K). A comparatively higher temperature coefficient of resistance of ∼−0.11%/K (improvement of ∼57%) was achieved in the Au/CNT nanocomposite bolometer (BM). Additionally, the composite BM demonstrated a dual (532 and 1064 nm) spectral selectively and enhanced sensitivity with respective large RT voltage responsivities of ∼11.70 ± 3.45 V/W and ∼503.54 ± 12.77 mV/W, as opposed to null response from the CNT BM. The current study, thus, demonstrates an important step toward designing high-performing CNT BMs for uncooled operation, with added functionality of wavelength-selectiveness. [ABSTRACT FROM AUTHOR]

Flexible optoelectronics is a rapidly growing field, with a wide range of potential applications. From wearable sensors to bendable solar cells, curved displays, and curved focal plane arrays, the possibilities are endless. The criticality of flexible photodetectors for many of these applications is acknowledged, however, devices that are demonstrated thus far are limited in their spectral range. In this study, flexible photodetectors are demonstrated using a VOx nanoparticle ink, with an extremely broad operating wavelength range of 0.4 to 20 µm. This ink is synthesized using a simple and scalable wet-chemical process. These photodetectors operate at room temperature and exhibit minimal variance in performance even when bent at angles of up to 100 ° at a bend radius of 6.4 mm. In addition, rigorous strain testing of 100 bend and release cycles revealed a photoresponse with a standard deviation of only 0.55%. This combination of mechanical flexibility, wide spectral response, and ease of fabrication makes these devices highly desirable for a wide range of applications, including low-cost wearable sensors and hyperspectral imaging systems.

Several new approaches to the measurement of intrinsic noise and dynamic characteristics of superconducting bolometers based on the RFTES technology are demonstrated. The developed methods were tested with an experimental 550–750 GHz sample at reading frequency of ~1.5 GHz at a temperature of 400 mK. The absorption of thin-film resistive coatings on sapphire and quartz substrates was studied, and the emissivity of the experimental heat source was estimated as ~14%. A shot noise source based on Al/AlOx/Al tunnel junction was developed, and the noise temperature of the 1.35–1.6 GHz buffer amplifier referred to the detector output was determined as ~20 K. The response time of RFTES with a hafnium film sized 6 × 2 × 0.08 μm was evaluated as ~3 μs via microwave heat modulation at the second resonance at ~4.2 GHz; the dynamic range at a modulation frequency of 10 kHz was more than 23 dB. The data obtained made it possible to determine the RFTES sensitivity as 1 × 1017 W/ ± 30%, that coincided with the theoretical value up to the measurement error. [ABSTRACT FROM AUTHOR]

Microbolometers have emerged as a cost‐effective alternative to cooled infrared photon detectors, albeit with certain trade‐offs in terms of responsivity (Rλ$R_{\lambda}$), detectivity (D*$D_{\*}$), and response time (tr$t_{\text{r}}$). The research in this field is driven by the potential applications in night vision devices, military surveillance, and autonomous vehicles, leading to a growing interest in exploring new materials to bridge the performance gap between cooled photon detectors and uncooled bolometers. This study focuses on the optoelectronic and bolometric characteristics of CuFeSe2$\left(\text{CuFeSe}\right)_{2}$ nanocrystals (NCs) in a colloidal solution. These NCs exhibit a significant change in resistivity (ρ) when subjected to temperature variations ranging from 170 to 400 K. Specifically, the temperature coefficient of resistance (TCR), α, is 1.9% per Kelvin for a room temperature resistivity of 505 Ω cm. Furthermore, the responsivity of CuFeSe2$\left(\text{CuFeSe}\right)_{2}$ NCs is reported to be 0.101 A W−1, and the Hall mobility of the colloidal solution is determined as 0.1 cm2 V s−1$0 \text{.1} \textrm{ } \left(\text{cm}\right)^{2} \textrm{ } \text{V} \textrm{ } \left(\text{s}\right)^{- 1}$. Finally, a comprehensive comparison is conducted between the performance metrics of established bolometer materials, such as VOx and a‐Si, and those of colloidal CuFeSe2$\left(\text{CuFeSe}\right)_{2}$ NCs. Based on the results, colloidal CuFeSe2$\left(\text{CuFeSe}\right)_{2}$ NCs are a promising option for future bolometer technology. [ABSTRACT FROM AUTHOR]

The Space High-Cadence Observing Telescope (SHOT) is proposed as a spaceborne 0.8-meter terahertz camera with remarkable imaging speed, aimed at conducting the inaugural large-sky terahertz survey and unlocking a pioneering realm for exploring the dynamic universe. Kinetic Inductance Bolometers (KIBs) represent a viable technique for the focal plane detector arrays of SHOT. In this paper, we present the design of a lumped-element kinetic inductance detector (LEKID) as the KIB detector, featuring various interdigital capacitors (IDCs) for tuning the resonator frequency. In KIB detector, the inductive component of the LEKID is thermally isolated from the substrate by a normal metal antenna, which serves to absorb terahertz signals. We conducted characterization on non-thermally isolated LEKID at temperatures of 1.5 and 0.01 Kelvin. The KIB design and fabrication processes have been established and the devices are fabricated with a 91.5% mechanical yield. The results form a foundation to build large arrays of KIB detectors using existing manufacturing technologies for SHOT. [ABSTRACT FROM AUTHOR]

This work reports the performance evaluation of an SDR readout system based on the latest generation (Gen3) of AMD's Radio-Frequency System-on-Chip (RFSoC) processing platform, which integrates a full-stack processing system and a powerful FPGA with up to 32 high-speed and high-resolution 14-bit Digital-to-Analog Converters and 14-bit Analog-to-Digital Converters. The proposed readout system uses a previously developed multi-band, double-conversion IQ RF-mixing board targeting a multiplexing factor of approximately 1000 bolometers in a bandwidth between 4 and 8 GHz, in line with state-of-the-art microwave SQUID multiplexers. The characterization of the system was performed in two stages, under the conditions typically imposed by the multiplexer and the cold readout circuit: first, in transmission, showing that noise and spurious levels of the generated tones are close to the values imposed by the cold readout, and second, in RF loopback, presenting noise values better than −100 dBc/Hz totally in agreement with the state-of-the-art readout systems. It was demonstrated that the RFSoC Gen3 device is a suitable enabling technology for the next generation of superconducting detector readout systems, reducing system complexity, increasing system integration, and achieving these goals without performance degradation. [ABSTRACT FROM AUTHOR]

Novel Mn 3 O 4 - LaMnO 3 composite ceramics have been successfully designed by the Pechini sol-gel routine, ceramics were calcined at 1450 °C for 12 h in air, and the electrical properties of its negative temperature coefficient at room temperature (300K) were investigated. X-ray diffraction and SEM results indicate that all the samples consist of two phases, LaMnO 3 and Mn 3 O 4 , and illustrate highly crystalline quality. The electrical transport measurements show that the temperature coefficient of resistance (TCR) vs. temperature of the composite presents a 'U' shape at wide-temperature-range(188–350K), which is beneficial for the performance of practical devices. Low resistivity ρ and TCR revealed for pure LaMnO 3 , While TCR and room temperature range were increased with the addition of Mn 3 O 4 phase into LaMnO 3. Enhanced electrical properties with moderate resistivity ρ make it a prominent and potential candidate to be utilized in portable, uncooled bolometer. [ABSTRACT FROM AUTHOR]

The transition-edge sensor (TES) as a type of low-temperature superconducting detector offers superior sensitivity due to its low thermal noise. In this work, we present a prototype TES bolometer designed for cosmic microwave background (CMB) polarization measurements. This TES is made of aluminum doped with a low concentration of manganese (2000 ppm by atomic percentage), and is deposited on the SiNx membrane which connects to the silicon substrate via narrow legs. In order to calculate its electrothermal parameters we have performed dark characterizations, which include measuring voltage-current (IV) curve at different bath temperatures, square-wave time response at various bias voltages, and noise level. This TES bolometer shows a noise equivalent power (NEP) of about 5 × 10 - 17 W/ Hz , which meets the requirement of CMB observation. However, its saturation power is smaller and time constant is larger than what are expected. We have analyzed the reasons and will make corresponding improvements in our future work. [ABSTRACT FROM AUTHOR]

We report picosecond bunch length measurements using an interferometric method for a 3 MeV electron beam having bunch charge ranging from 1 to 14 pC. The method senses the single-cycle sub-terahertz (THz) pulse emitted by each electron bunch as coherent transition radiation which, in turn, is analyzed using a Michelson-type interferometer, forming an interferogram that is then processed to yield the nominal electron bunch length. This sub-THz coherent radiation intensity was measured using a quasi-optical detector (QOD) operated at room temperature. This experiment was quite challenging since the divergence angle of the sub-THz pulse emitted by the low-energy electron bunch exceeds ±10°, and its pulse energy at the entrance to the detector was as low as 100 pJ. When compared to a conventional helium-cooled silicon composite bolometer designed for frequencies above 0.5 THz, the QOD provided much better signal-to-noise ratio in the ∼80 GHz frequency range, which was critical for the successful measurement of the bunch length. [ABSTRACT FROM AUTHOR]

Facile-prepared films with a high-temperature coefficient of resistivity (TCR) are crucial for application in high-sensitivity bolometers. In this study, La 0.7 Ca 0.25 K 0.05 MnO 3 (LCKMO) films were grown on (001)-oriented La 0.3 Sr 0.7 Al 0.65 Ta 0.35 O 3 (LSAT) substrates using the spin-coating method. Various sintering temperatures (900 °C ≤ T s ≤ 1050 °C) were utilized in the film preparation, causing the lattice mismatch between films and substrate degraded. The effect of T s on the strain state of films was investigated through X-ray diffraction (XRD) analysis. The distortion of MnO 6 octahedra and the Mn–O bond were assessed using Raman and FTIR spectra, respectively. The structural perfection and elemental valence of films were adjusted via optimizing T s. Meanwhile, the strain state and defect structure were effectively improved with T s increasing. These results indicate that the LCKMO films with high crystalline quality can be achieved by optimizing the sintering process. The TCR of LCKMO films was modified. When T s at 1000 °C, the LCKMO films exhibit the remarkable TCR of 16.29% K-1 at 269.54 K, indicating the substantial potential of LCKMO films in infrared bolometers. [ABSTRACT FROM AUTHOR]

The focal plane of a telescope for cosmic microwave background (CMB) observation typically contains a large-scale array of transition-edge sensor (TES) bolometers. Polarized planar antennas are easy to fabricate and integrate, compared to commonly used horn antennas in receiving modules. In order to enhance the directivity and coupling efficiency, a planar antenna is generally equipped with a hyper-hemispherical silicon lens. However, a Si lens has a large volume, and the fabrication and assembly processes are complex. A flat all-dielectric metasurface lens is proposed to replace Si-lens to converge beam and increase gain of a slot antenna. The all-dielectric structure of silicon holes with sub-wavelength thickness can change the volumetric fill factor to adjust the local effective refractive index, and thus manipulate the shape of wavefront while ensuring high transmission efficiency. The meta-lens was found to exhibit high gain, low cross polarization and good beam symmetry, as verified by simulated electric field amplitude distribution and far-field patterns at 225 GHz using CST microwave studio suite. The detector array and the meta-lens array can both be fabricated using standard planar photolithography technology, and the combination has the potential to achieve larger scale arrays. [ABSTRACT FROM AUTHOR]

The AnaBHEL experiment aims to detect the analog Hawking radiation emitted by an accelerated relativistic plasma mirror for which the effective event horizon is analogous to that of a black hole, thanks to the equivalence principle. This radiation is composed of a few Hawking photons emitted simultaneously in the infrared band and the 'partner photons' in the ultraviolet band. The former is emitted in the opposite direction of the mirror propagation and is redshifted in the laboratory frame. In the AnaBHEL scheme, high-intensity petawatt laser pulses, will be used to produce the relativistic accelerated plasma mirrors from a helium gas jet. Infrared and ultraviolet photons generated by the mirrors will be detected by dedicated superconducting nanowire single-photon detectors (SNSPDs) at very low temperature and by multichannel plates at room temperature, respectively. Details of the setup design are discussed. [ABSTRACT FROM AUTHOR]

The future Ricochet experiment aims to search for new physics in the electroweak sector by measuring the Coherent Elastic Neutrino-Nucleus Scattering process from reactor antineutrinos with high precision down to the sub-100 eV nuclear recoil energy range. While the Ricochet collaboration is currently building the experimental setup at the reactor site, it is also finalizing the cryogenic detector arrays that will be integrated into the cryostat at the Institut Laue Langevin in early 2024. In this paper, we report on recent progress from the Ge cryogenic detector technology, called the CryoCube. More specifically, we present the first demonstration of a 30 eVee (electron equivalent) baseline ionization resolution (RMS) achieved with an early design of the detector assembly and its dedicated High Electron Mobility Transistor (HEMT) based front-end electronics with a total input capacitance of about 40 pF. This represents an order of magnitude improvement over the best ionization resolutions obtained on similar phonon-and-ionization germanium cryogenic detectors from the EDELWEISS and SuperCDMS dark matter experiments, and a factor of three improvement compared to the first fully-cryogenic HEMT-based preamplifier coupled to a CDMS-II germanium detector with a total input capacitance of 250 pF. Additionally, we discuss the implications of these results in the context of the future Ricochet experiment and its expected background mitigation performance. [ABSTRACT FROM AUTHOR]

On‐chip photodetectors are essential components in optical communications as they convert light into an electrical signal. Photobolometers are a type of photodetector that functions through a resistance change caused by electronic temperature fluctuations upon light absorption. They are widely used in the broad wavelength range from ultraviolet to mid‐infrared (MIR). In this work, a novel waveguide‐integrated bolometer that operates in a wide wavelength range from near‐infrared to MIR is introduced on the standard material platform with the transparent conductive oxides (TCOs) as the active material. This material platform enables the construction of both modulators and photodetectors using the same material, which is fully complementary metal–oxide–semiconductor compatible and easily integrated with passive on‐chip components. The photobolometers proposed here consist of a thin TCO layer placed inside the rib photonic waveguide to enhance light absorption and then heat the electrons in the TCO. This rise in electron temperature leads to decreasing electron mobility and consequential electrical resistance change. In consequence, a responsivity exceeding 10 A W−1 can be attained with a mere few microwatts of optical input power. Calculations suggest that further improvements can be expected with lower doping of the TCO, thus opening new doors in on‐chip photodetectors. [ABSTRACT FROM AUTHOR]

It is known that the dielectric layer (resonator) located behind the conducting plate of the bolometer system can significantly increase its sensitivity near the resonance frequencies. In this paper, the possibility of receiving broadband electromagnetic signals in a multilayer bolometric meta-material made of alternating conducting (e.g., silicon semiconductor) and dielectric layers is demonstrated both experimentally and numerically. It is shown that such a multilayer structure acts as a lattice of resonators and can significantly increase the width of the frequency band of efficient electromagnetic energy absorption. The parameters of the dielectric and semiconductor layers determine the frequency bands. Numerical modeling of the effect has been carried out under the conditions of our experiment. The numerical results show acceptable qualitative agreement with the experimental data. This study develops the previously proposed technique of resonant absorption of electromagnetic signals in bolometric structures. [ABSTRACT FROM AUTHOR]

On present-day magnetic-confinement fusion experiments, the performance of multi-channel bolometer diagnostics has typically evolved over time through experience with earlier versions of the diagnostic and experimental results obtained. For future large-scale fusion experiments and reactors, it is necessary to be able to predict the performance as a function of design decisions and constraints. A methodology has been developed to predict the accuracy with which the volume-integrated total radiated power can be estimated from the measurements by a resistive bolometer diagnostic, considering, in particular, its line-of-sight geometry, étendues of individual lines of sight, bolometer-sensor characteristics, and the expected noise level that can be obtained with its electronics and signal chain. The methodology depends on a number of assumptions in order to arrive at analytical expressions but does not restrict the final implementation of data-processing of the diagnostic measurements. The methodology allows us to predict the performance in terms of accuracy, total-radiated power level, and frequency or time resolution and to optimize bolometer-sensor characteristics for a set of performance requirements. This is illustrated for the bolometer diagnostic that is being designed for the ITER experiment. The reasonableness, consequences, and limitations of the assumptions are discussed in detail. [ABSTRACT FROM AUTHOR]

Many applications require monitoring of increasingly high neutron flux levels. Pre‐neutron characterization is performed of a superconducting transition edge bolometric device, sensitive to neutrons by an enriched boron carbide (10B4C) layer. Heat from the absorption of neutrons is simulated using an attenuated laser, while the detector is cooled to the critical temperature, Tc. Frequency dependent (4–25 Hz) and constant input power measurements are performed on a 10B4C‐coated and a non‐coated pixel. Results are used to fit a two lumped element thermal model. The effective specific heat is highly dependent on the input pulse duration due to the interconnected stack structure. For modulated pulses, the active volume in the thermal circuit is the full depth of the substrate in the area under the pixel. For constant power input, a large portion of the substrate is heated and the interface conductivities to the cold finger are found to be important. The detectivity is D* = 3.5 × 108 cmHzW−1${{\rm cm}} \sqrt {{\rm Hz}}\,{{\rm W}^{-1}}$, and is only slightly lower than similar detectors. Understanding the dynamics of the detector better and using neutron excitation, it is expected that optimizations can lead to an equally good detector for cold to thermal neutrons at flux levels >106 n cm−2s−1. [ABSTRACT FROM AUTHOR]

In this paper, the design and optimization of a wideband THz metamaterial absorber (MMA) are proposed. By simulation, we reached four structures with absorptions higher than 50%, 70%, 80%, and 90%, with relative absorption bandwidths (RABWs) of 1.43, 1.29, 0.93, and 0.72, respectively. Terahertz absorbers can be used in many potential applications, such as in imaging, energy harvesting, scattering reduction, and thermal sensing. Our intended application was to use the optimal absorber on a thermal detector for detectivity over a wide THz range. Since broadband absorption in the range of 0.3 to 2 terahertz is considered for use in medical imaging, the MMA with more than 50% absorption in the range of 0.35-2.1 THz was selected. The designs were also intended to have the capability of being implemented on different devices, such as bolometers. The cost of the fabrication of the proposed absorber was also low because of the implementation of a single-layer MMA design and the utilization of affordable and more accessible materials and techniques. Our proposed structure had a minimum feature size of 3 μm, making the fabrication process convenient using the standard photolithography method as well. We used thin layers of nickel as the metal for both the single-layer pattern and ground layer, which were placed on the front and back sides of the structure, respectively. The nickel thin film layers were deposited using the sputtering technique and separated by a dielectric layer. The material chosen for the dielectric layer was SU8, which has proper electromagnetic properties and also good adhesion to nickel. Characterization of the fabricated absorber was performed using a terahertz spectroscopy system, and the experimental results verified the high absorption of the sample. [ABSTRACT FROM AUTHOR]

Needs for neutron detection and monitoring in high neutron flux environments are increasing in several different fields. A completely solid-state, current mode bolometric detector is constructed as a solid substrate transition edge sensor based on a high-T c superconducting meander. The detector consists of four individual pixels of which three pixels include 10 B 4 C neutron absorption layers. The absorbed energy per neutron absorption reaction is modelled and compared to experimental data. The response of the tested detector is directly correlated to a cold neutron beam with a flux of 1.8 × 10 8 n / cm 2 / s modulated by a slit. The signal is found to be an order of magnitude higher than the thermal background. The dynamics described by the temporal saturation constants is governed by a modulation frequency less than 1 Hz . The thermal response is dynamic and never fully saturates for 50 s exposures. The efficiency for this proof-of-principle design is 1–2%. Possibilities for optimization are identified, that will increase the efficiency to become comparable to existing solid boron-10 detectors. The existing detectors with event-based read-out have limited functionality in high flux environments. The superconducting bolometer described in this work using current-mode readout will pave the way for high flux applications. [ABSTRACT FROM AUTHOR]

Analytical relations for temperature response of the bolometer to periodic radiation pulses are obtained. It is theoretically shown and experimentally confirmed by the example of infrared bolometers that when detecting short radiation pulses, in contrast to the case of constant radiation, increasing the thermal conductivity of the bolometer and, accordingly, decreasing its thermal relaxation time, it is possible to significantly increase the response rate of the receiver, practically without reducing its sensitivity. The possibility of effective registration of pulsed terahertz radiation by microbolometers with a resistively coupled, thermally non-isolated antenna is considered. It is shown that such bolometers, which have increased thermal conductivity and, accordingly, reduced sensitivity to continuous-wave radiation, can be highly effective when detecting pulsed radiation with a duration shorter than the thermal relaxation time of the bolometer. On their basis, uncooled matrix detectors of pulsed terahertz radiation, characterized by a minimum detectable energy of less than 1 × 10–12 J and a frame rate of up to 1000 Hz, can be developed. [ABSTRACT FROM AUTHOR]