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Infrared camouflage is an effective technique to avoid many kinds of target detection by detectors in the infrared band. For a high-temperature environment, thermal management of selective emission is crucial to dissipate heat in the mid-infrared non-atmospheric window (5–8 μm). However, it still remains challenges for balancing infrared camouflage and thermal management. Here, we experimentally demonstrate a multilayer film structure (MFS) for infrared camouflage with thermal management. Combining the ideal emission spectrum and genetic algorithm (GA), the inverse-design MFS containing 7 layers of five materials (SiO2, Ge, ZnS, Pt and Au) has been designed. Based on the hierarchical metamaterial, the optimized MFS has high performance of infrared camouflage to against the lidar detection in the near-infrared band. The experimental results reveal the high compatible efficiency among thermal camouflage (ε3–5μm = 0.21, ε8–14μm = 0.16), laser stealth (ε1.06μm = 0.64, ε1.55μm = 0.90, ε10.6μm = 0.76) and thermal management (ε5–8μm = 0.54). Therefore, the proposed MFSs are attractive as basic building block of selective emitter, for the application of advanced photonics such as radiative cooling, infrared camouflage, and thermal emission.

High-performance terahertz wave detectors at room temperature are still urgently required for a wide range of applications. The available technologies, however, are plagued by low sensitivity, narrow spectral bandwidth, complicated structure, and high noise equivalent power (NEP). Here, we have demonstrated a Weyl semimetal surface plasmon-enhanced high-performance terahertz wave detectors which are based on microdisk array deposited WTe2 nanofilm epitaxially grown on GaN substrate for room temperature operation. With the microdisk array combined the WTe2 layer, strong terahertz wave surface plasmon polaritons can be generated at the WTe2–air interfaces, which results in significant improvement in detecting performance. For the 40 μm diameter microdisk array, a detectivity (D *) of 5.52 × 1012 cm Hz1/2 pW−1 at 0.1 THz is achieved at room temperature. In addition, the responsivity (R A) of 8.78 A W−1 is also obtained. Such high-performance millimeter and terahertz wave photodetectors are useful for wide applications such as high capacity communications, walk-through security, biological diagnosis, spectroscopy, and remote sensing.

It is particularly appealing for efficient active terahertz (THz) modulators using photonic structures to enhance light–matter interaction. Here, an optical controlled THz modulator is proposed that combines lead sulfide (PbS) quantum dots with subwavelength metallic split-ring resonators (SRRs) for providing field enhancement. The modulation depth reaches 60.3%, which is approximately 3 times larger than the PbS quantum dots film without SRRs (as reference) in the frequency range of 0.1–1.1 THz. Such significant enhanced THz modulation is mainly due to the local THz field enhancement caused by the SRRs, which is consistent with the simulation result.

Ti3C2Tx materials have been developed to have application space in many fields, but there are not many works that can be compatible with infrared (IR) stealth and electromagnetic interference (EMI) shielding at the same time. To realize the multiband high EMI shielding of Ti3C2Tx materials, and to achieve stealth effect in the IR band, in this work, a composite textile is prepared by combining the Ti3C2Tx material with a carbon cloth and sputtering a very thin gold film on the surface. This composite textile can realize high EMI shielding compatible with IR stealth, in which the EMI shielding efficiency for microwave Xa‐band (8GHza‐12.4GHz) is up to 71.8 dB, for microwave Kaa‐band (26.5GHza‐40GHz) is up to 75.02 dB, and for terahertza‐band is about 30 dB. IR emissivity is as low as 0.1, and the lowest emissivity under a certain temperature reaches 0.07, which can withstand a high temperature of 500 °C. In addition, this composite textile has flexible and bendable wear. The thickness of the whole textile is about 400 µm, of which the Ti3C2Tx material thickness is only about 10 µm, the thinnest reaches 2 µm. Such a textile can be used in both people's livelihood and military applications, which has far‐reaching significance. [ABSTRACT FROM AUTHOR]

Thulium-doped fiber lasers (TDFLs) operating at 1.7 μm have immense potential for multiphoton microscopy and imaging applications. However, further research and development are needed, particularly in the ultra-short wavelength range below 1720 nm. Herein, we demonstrate the mode-locked TDFL at 1.7 μm, utilizing a microfiber InSb saturable absorber. By employing intracavity filters, optimizing the gain fiber length, and incorporating a broadband evanescent field absorber, we achieve high-performance ultra-short wavelength solitons in the TDFL. The solitons exhibit a central wavelength of 1707 nm, a pulse width of 895 fs, a repetition rate of 23.36 MHz, and a single pulse energy of 1.7 nJ. Moreover, our experiments demonstrate the generation of diverse soliton states, including high-order harmonic and bound solitons. We also explore the dynamics of mode-locking through experimental investigations. Our findings establish a solid foundation for the research and control of diverse 1.7 μm mode-locked operation state, advancing the field of ultrafast fiber lasers in this wavelength band. [ABSTRACT FROM AUTHOR]

Pulse lasers with an output wavelength of 976 nm play an important role in scientific research and industrial fields. Using a nonlinear optical loop mirror (NOLM), we build a 976 nm mode-locked fiber laser with a figure-9 resonant cavity. By adding a 30 m passive fiber to the loop mirror, the noise-like pulses (NLPs) with a repetition frequency of 4.79 MHz, a maximal average output power of 13.35 mW and corresponding pulse energy of 2.79 nJ, are achieved. Furthermore, the variation of the pulse characteristics at different pump powers is investigated. The pulse energy and pulse width both increase with increasing pump power, but the coherent peak width in the autocorrelation curve decreases with increasing pump power. The laser provides a simple and costeffective solution for the generation of 976 nm noise-like pulses, which has potential application value in the generation of supercontinuum spectrum and the study of noise-like pulse dynamics. [ABSTRACT FROM AUTHOR]

Noise‐like pulses (NLPs) are becoming increasingly attractive for a variety of applications such as supercontinuum generation, materials processing, and low‐coherence spectral interferometry. Related research in the near‐infrared region is extensive, yet few studies have been reported in the mid‐infrared (MIR) region. Herein, a systematic investigation of MIR NLPs is made for the first time. An approach is presented by exploiting a polarization‐maintaining fluoride fiber in the mode‐locked oscillator to cause a polarization‐dependent delay between the orthogonal‐polarized components of intracavity circulating pulses, thus generating a series of ultrashort pulses which will eventually form a stable wave packet, namely, NLP. Numerical simulations based on the extended coupled nonlinear Schrödinger equations predict the generation of NLPs, and reveal key aspects of the pulse evolution. Experiments yield linearly polarized NLPs at 2.8 μm with a maximum average power of 498 mW and a spike width of 4.3 ps, corresponding to a pulse energy of 12 nJ. The experimental results are in good agreement with the simulation results. This work constitutes a major step toward the development of MIR ultrafast fiber lasers with NLPs output. [ABSTRACT FROM AUTHOR]

Plasmonic nanolasers as a new class of coherent laser beyond the diffraction limit have attracted a lot of attention. However, the ultrahigh optical confinement caused by the plasmon effect is inevitably accompanied by metal absorption loss, thus increasing the pump threshold of the plasmonic nanolaser. In the past decade, many good results about low threshold plasmonic nanolasers have been realized and successfully extended to various applications. Here, this advance is discussed and some opinions are offered. First, based on the theoretical model and key parameters of the plasmonic nanolaser, the factors affecting the threshold are analyzed. Subsequently, the experimental efforts on the realization of low threshold plasmonic nanolasers from optical pumping to electrical pumping are reviewed. Their applications in on‐chip optical interconnects, biochemical analysis, and far‐field structure are then considered. Finally, feasible approaches to threshold reduction are discussed, as well as more possible applications in the future. [ABSTRACT FROM AUTHOR]

Due to the low photon energy in the relevant frequency band, fewer materials can directly excite carriers, and an extreme lack of high‐performance, large‐area detectors, limit the promotion, and development of 6G technology. In addition, flexible detectors with the integration of 6G communication and Internet of Things technology has good prospects for application in the development of optoelectronic devices, which are also urgently needed. A large‐area flexible thin layer terahertz detector is designed that combines the advantages of excellent optoelectronic performance in the detection of electromagnetic waves with low photon energy and the localized surface plasmon (LSP) effect in a sub‐wavelength structure detector. Due to the large effective area, the spiral electrode device demonstrates the best performance at room temperature. The noise equivalent power (NEP) and photoresponsivity (RV) are achieved with 0.4 pW Hz−1/2 and 154 MV W−1 at 0.28 THz. In addition, the bending experiments show that the device has extreme advantages for flexible 6G detector applications. [ABSTRACT FROM AUTHOR]

The Chinese Fusion Engineering Test Reactor (CFETR) is a magnetic confinement fusion reactor independently designed and developed by China, which is based on the ITER design experience. As one of the candidates for the CFETR, the water cooled ceramic blanket (WCCB) mainly carries out many important tasks, such as tritium breeding and radiation shielding. The high tritium breeding ability is one of the most significant goals of the blanket. For the design of the CFETR, in addition to meeting the requirements of tritium breeding, the design of the blanket must also consider meeting relevant shielding limits. Due to the limited space of the blanket, the improvement in tritium breeding space will inevitably lead to the reduction in neutron shielding space behind the breeding area, and vice versa. Therefore, under the premise of meeting the requirements of neutron shielding, increasing the tritium breeding space as much as possible is the focus of research. In this work, a three-dimensional neutronics model containing the WCCB blanket is developed, and the neutronics performance is calculated based on 1.5 GW fusion power. A set of nuclear analyses are carried out by the MCNP code, including analysis of the neutron wall load, tritium breeding ratio (TBR), and fast neutron fluence of the TF coil. It is found that the shielding space of certain blanket modules could be optimized. After the shielding optimization, the global TBR increased from 1.168 to 1.186, an increase of 0.018 TBR. The current research has important guiding significance for the future design and optimization of the WCCB for the CFETR. [ABSTRACT FROM AUTHOR]