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Single excitons in semiconductor microcavities represent a solid state and scalable platform for cavity quantum electrodynamics, potentially enabling an interface between flying (photon) and static (exciton) quantum bits in future quantum networks. While both single-photon emission and the strong coupling regime have been demonstrated, further progress has been hampered by the inability to control the coherent evolution of the cavity quantum electrodynamics system in real time, as needed to produce and harness charge–photon entanglement. Here using the ultrafast electrical tuning of the exciton energy in a photonic crystal diode, we demonstrate the dynamic control of the coupling of a single exciton to a photonic crystal cavity mode on a sub-nanosecond timescale, faster than the natural lifetime of the exciton. This opens the way to the control of single-photon waveforms, as needed for quantum interfaces, and to the real-time control of solid-state cavity quantum electrodynamics systems., Controlling the coherent evolution of cavity quantum electrodynamics systems is key for future quantum networks. Here Pagliano et al. demonstrate dynamic control of the coupling of a single exciton to a photonic micro-resonator using electrical tuning of the exciton energy in a photonic crystal cavity diode.

We report the control over the spontaneous emission of energy-tunable quantum emitters embedded in passive waveguide circuits, realized by coupling Stark-tunable quantum dots to electromechanically-compliant photonic crystal molecules.

We report a high resolution wavelength and displacement sensor based on an electromechanically tuneable photonic crystal cavity, where sensing, actuation and electrical readout are integrated together in the same device.

Macro-modelling approaches are widely used for assessing the effects of infill panels. However, they contain some specific uncertainties concerning the definition of the equivalent strut (such as the width of the strut, the non-linear constitutive law under cyclic actions and assignment of mechanical properties in multiple strut models) that causes the variability of global structural response. As a result, there is the need to identify what are the parameters that influence the overall response of the building. After the identification of significant parameters, it is crucial to quantify the variation of the results regarding the safety verification of the building. In order to investigate this aspect, for two existing buildings with different heights, using a range of permissible values, the characteristic points (yield strength and maximum point) of the cyclic non-linear law were changed. The procedure has been carried out with the other preliminarily fixed parameters of the equivalent struts. With this approach, a variation of the safety in performance terms was assessed by carrying out a sensitivity analysis of the non-linear cyclic law. The results proposed lay the foundations for further consideration of issues relating to the modelling uncertainties and the development of simplified models for the assessment of existing structures designed to withstand only vertical loads.

A novel photon-number-resolving detector (PNRD) structure, based on an array of nanowire superconducting single photon detectors (SSPDs) connected in series, have recently been proposed. With this configuration, it is possible to scale to large photon numbers. In this framework, PNRDs capable of resolving up to four, eight and twelve photons at telecommunication wavelengths have been fabricated and tested. The photon-induced voltage signals from all the series elements are summed up into a single readout pulse with a height proportional to the detected photon number. Analysis of the linearity shows the potential of scaling to an even larger dynamic range. © 2014 AEIT.

We demonstrate the integration of a new and scalable photon-number-resolving detector (PNRD) based on a spatially multiplexed array of superconducting nanowire single photon detectors (SSPDs) connected in series. The waveguide photon number resolving detectors (WPNR) show a device quantum efficiency of 24% and can discriminate between 0-4 photons.

Solid-state cavity quantum electrodynamics systems will form scalable nodes of future quantum networks, allowing the storage, processing and retrieval of quantum bits, where a real-time control of the radiative interaction in the cavity is required to achieve high efficiency. We demonstrate here the dynamic molding of the vacuum field in a coupled-cavity system to achieve the ultrafast nonlocal modulation of spontaneous emission of quantum dots in photonic crystal cavities, on a timescale of ~200 ps, much faster than their natural radiative lifetimes. This opens the way to the ultrafast control of semiconductor-based cavity quantum electrodynamics systems for application in quantum interfaces and to a new class of ultrafast lasers based on nano-photonic cavities., Comment: 15 pages, 4 figures

Aims: The objective of this study was to determine the presence of infectious hepatitis A virus (HAV) in molluscs naturally contaminated with viral HAV-RNA. Methods and Results: One hundred and forty-two mollusc samples were analysed for the presence of viral HAV-RNA using RT-nested-PCR; positive samples were then analysed with an integrated method, cell-culture RT-PCR, to detect infectious virus. Viral HAV-RNA was detected in 34·5% of the samples while 12·7% of the total samples were positive for the presence of infectious virus. Conclusions: The results demonstrate the validity of the screening method (RT-nested-PCR) and the necessity of applying a method that is capable of detecting the presence of infectious HAV. Significance and Impact of the Study: The study demonstrates that in any case, to determine the safety for human consumption, the results of RT-nested-PCR must be confirmed with an integrated cell-culture PCR method.

We report direct evidence of enhanced spontaneous emission in a photonic crystal light-emitting diode (LED) at telecom wavelength (lambda similar to 1300 nm). This result is crucial to obtain an electrically driven single photon source with high extraction efficiency. This kind of devices can be used for different types of applications in emerging fields like quantum key distribution, quantum information technology as well as in fundamental studies on quantum electrodynamics. In this work we present a device which combines a photonic crystal nanocavity with InAs quantum dots (QDs) and an LED, leading to cavity-enhanced emission at telecom wavelengths under electrical injection. The fabrication process, based on e-beam lithography and additive and subtractive processes, is described in detail. A well-isolated emission peak at about 1300 nm from the PhC mode electrically pumped is obtained (Q similar to 4000), and the enhancement of the spontaneous emission rate (similar to 1.5 fold) is clearly evidenced by time-resolved electroluminescence measurements. (C) 2008 Elsevier B.V. All rights reserved.

We directly investigate, by means of near-field spectroscopy, the spatial distribution of the optical cavity modes of 2D photonic crystal microcavities. Numerical simulations confirm that the photoluminescence maps of quantum dots embedded in the photonic structure qualitatively match the spatial modulation of the electric field intensity. (C) 2007 Elsevier B.V. All rights reserved.

A method for the detection of HAV in shellfish, based on the use of guanidinium isothiocyanate-containing solution for RNA extraction and purification steps, followed by nested PCR, is hereby proposed. Tests were carried out on mollusc samples spiked with HAV strain FG. Results showed that in samples subjected only to one round of PCR it was possible to detect HAV at concentrations of 10 3 –10 4 TCID 50 /10 g of mollusc. The use of the nested PCR renders the system more sensitive and specific enabling the identification of HAV concentrations as low as 1 TCID 50 /10 g of mollusc. Furthermore thus method, in addition to allowing the avoidance of confirming tests, such as hybridization, proved to be inexpensive and simple to perform.

Combined lateral-vertical oxidation of AlGaAs is investigated as a means of tuning the resonant wavelength of a semiconductor microcavity after the epitaxial growth. It is shown that this technique can provide arrays with a wavelength spread equal to the cavity's free spectral range with a single postgrowth processing step. Design issues for multiple-wavelength vertical-cavity laser arrays using this postgrowth tuning technique are discussed, comparing the performance of devices with all-semiconductor and partially or totally oxidized Bragg mirrors. Experimental results are presented on arrays with a 48-nm lasing span around 970 nm, using partially and totally oxidized mirrors.

We analyze the scaling characteristics of the optical and current confinement for three different vertical-cavity surface-emitting laser (VCSEL) structures with tapered apertures. The improvements in scaling have allowed devices with apertures

Frequency conversion in nonlinear optical crystals is an effective means of generating coherent light at frequencies where lasers perform poorly or are unavailable. For efficient conversion, it is necessary to compensate for optical dispersion, which results in different phase velocities for light of different frequencies. In anisotropic birefringent crystals such as LiNbO3 or KH2PO4 ('KDP'), phase matching can be achieved between electromagnetic waves having different polarizations. But this is not possible for optically isotropic materials, and as a result, cubic materials such as GaAs (which otherwise have attractive nonlinear optical properties) were little exploited for frequency conversion applications. Quasi-phase-matching schemes, which have achieved considerable success in LiNbO3, provide a route to circumventing this problem, but the difficulty of producing the required pattern of nonlinear properties in isotropic materials, particularly semiconductors, has limited the practical utility of such approaches. Here we demonstrate a different route to phase matching-based on a concept proposed by Van der Ziel 22 yr ago (Appl. Phys. Lett., 1975) which exploits the artificial birefringence of multilayer composites of GaAs and oxidized AlAs. As GaAs is the material of choice for semiconductor lasers, such optical sources could be integrated in the core of frequency converters based on these composite structures. [on SciFinder (R)]

We demonstrate the use of p-doping in the active region of quantum-dot superluminescent diodes. Modal gain measurements and light output-current characteristics prove that p-doping is beneficial for achieving higher gain, higher output power, and better temperature stability

The dynamic behaviour of an existing building is sometimes difficult to predict, particularly when the information available for the specific case study is not as much as would be necessary for a complete description of the structure. Dynamic response to vibration induced by external natural/artificial sources, thanks to the relative ease with which it can be measured and analysed, makes vibration-based assessment an attractive complement to traditional visual inspection and nondestructive evaluation methods. This study moves from an investigation that is being carried out on a building sited in the port area of Bari, Apulia, where excavation and dredging operations are thought to be responsible for a series of damage that could involve structural and non structural elements in the monitored buildings due to vibration induced in the entire surrounding area. Having the chance to measure the real acceleration and displacement at the basement floor and in some other relevant parts of the building, it will be possible to update the finite element model, matching the response of the FE model in a series of combinations of parameters with the real measured dynamic excitation. Many other studies regarding dynamic identification and the usual modern methods make use of ambient-vibration induced by the so-called environmental noise or, otherwise, inducing a dynamic response by artificial sources of vibration. In this research work the source is known in terms of frequency and magnitude and, so, with an adaptive procedure it will be possible to predict the future damage, serviceability loss or, more generally, the performance of the building towards different combinations of static and dynamic loads.

Densely integrated light sources are essential for centimeter scale data communication. In this paper we examine the factors and challenges influencing the efficiency of such devices. We then focus on studying the performance of reflector and out-coupling concepts using finite different time domain simulations. Keywords: integrated photonics, nanolasers, reflectors, waveguide-coupling.

In assessing the safety of existing buildings, the specific actions dedicated to the knowledge of the structure delineate the parameters of the linear or non-linear analysis aimed at identifying the most appropriate structural intervention. In this context, the present paper collects the seismic analysis of a school building in reinforced concrete, illustrating the different stages concerning the acquisition of geometrical and mechanical data, problems about structural modelling and the features of the seismic retrofitting proposed. In closing, a critical comparison between the results derived from some techniques frequently used to seismically improve existing structures.

The experimental demonstration of a superconducting photon-number-resolving detector, based on the series connection of N superconducting nanowires, is presented. An integrated resistor is connected in parallel to each section of the device that provides in this way a single voltage-readout, proportional to the number of photons detected in distinct nanowires. As a proof of principle a four element detector has been fabricated from an NbN film on a GaAs substrate and fully characterized. Clearly separated output levels corresponding to the detection of n = 1-4 photons are observed achieving a single-photon system quantum efficiency of 2.6% at ?=1.3 ?m. In order to demonstrate the potential scalability of the series-nanowire detector to a larger number of photons, we report our preliminary results in the characterization of detectors fabricated with 8 and 12 pixels. Clear evidence of n= 1-8 photon absorption in the 8-pixel detector has been achieved. © Published under licence by IOP Publishing Ltd.

We discuss relevant design considerations for the fabrication of electromechanically tunable photonic crystal cavities based on double semiconductor slabs. A simple optical and electromechanical model of the device based on coupled-mode theory and electrostatics is discussed and used jointly with 3-D finite-element calculations of optical cavity modes to extract the tuning-range dependence on geometrical parameters. A design rule, which avoids the sticking of membranes due to capillary forces and keeps a large tunability, is defined. The details of the fabrication process and a summary of the experimental results on GaAs and InGaAsP/InP material systems are given. We also address the problem of nonsymmetric devices, where the thicknesses of the membranes are not exactly the same, resulting in an imbalanced power emission of coupled modes.

We introduced, characterized and modeled a simple nanodetector to investigate the efficiency and yield limitations of NbN superconducting single photon detectors. These crucial issues are related to the detectors strongly inhomogeneous nature at the nanoscale.

We report ridge-waveguide superluminescent diodes based on five stacks of self-assembled InAs-GaAs quantum dots. Devices with output powers up to 10 mW emitting around 1.3 /spl mu/m are demonstrated. Spectral analysis shows a broad emission peak (26-nm full-width at half-maximum) from the dot ground state at low injection, and an additional peak from the excited state at higher bias. Temperature characteristics in the range 10/spl deg/C-80/spl deg/C are also reported. The experimental curves are in good agreement with simulations performed using a traveling-wave rate equation model.

We demonstrate a superconducting photon-number-resolving detector capable of resolving up to twelve photons at telecommunication wavelengths. It is based on a series array of twelve superconducting NbN nanowire elements, each connected in parallel with an integrated resistor. The photon-induced voltage signals from the twelve elements are summed up into a single readout pulse with a height proportional to the detected photon number. Thirteen distinct output levels corresponding to the detection of n=0-12 photons are observed experimentally. A detailed analysis of the excess noise shows the potential of scaling to an even larger dynamic range., 13 pages

We present a quantum integrated photonics platform on GaAs including waveguide single-photon sources and detectors on the same chip.

We report a study of single quantum dots inside photonic crystal cavities with a low-temperature scanning near-field optical microscope. The spatial maps of single excitonic lines from the quantum dot show the clear signature of coupling to the cavity modes for small detunings. We also show that the near-field tip can be used to control the exciton-photon coupling at the nanoscale. A general framework for the interpretation of near-field maps of single emitters in cavities is proposed.

We report the electromechanical control of spontaneous emission of single InAs quantum dots (QDs) embedded in wavelength-tunable double-membrane photonic crystal cavities (PCC). The tuning is achieved by modulating the distance between two parallel GaAs membranes by applying electrostatic forces across a p-i-n diode under reverse bias. The spontaneous emission rate of single dots has been modified by over a factor of ten, tuning the cavity reversibly between on- and offresonant conditions without altering the emission energy of the dots. We also discuss a possible approach to integrate the double membrane structure with ridge waveguides, for the transmission of light within a photonic chip.

We present a device for the spectral reconfiguration of a two-dimensional photonic crystal cavity (PCC) based on parallel semiconductor membranes. The mechanical motion of the slabs introduces a variation in the effective refractive index of the coupled waveguides where the photonic crystal is etched resulting in a shift of the free-space wavelength. Using an integrated electrostatic actuator we demonstrated independent tuning up to 15 nm with less than 6 V bias. We present the electromechanical control of a PCC mode in resonance to single quantum dot (QD) emission lines for the real-time compensation of the spectral mismatch due to the dots' inhomogeneity. We discuss the operation of the device at low temperatures (

Semiconductor nanolasers provide an attractive route towards high density photonic integrated circuits in low power applications such as optical interconnects. In this paper we present the concept of a waveguide-coupled nanolaser for integration in a CMOS compatible photonic platform. We exploit metallic and dielectric confinement to provide high quality factors exceeding 500 in a wavelength-scale cavity, that provides efficient cooling and cross-talk immunity due to the metal coverage. We present simulations detailing the design considerations for high quality factors and efficient waveguide coupling. Optical and electrical simulations predict room temperature operation at 1.55 μm with a threshold current of 120 μA and a differential quantum efficiency of 0.16. We also discuss briefly the challenges of fabricating these devices and integrating them in the photonic platform.

The generation, manipulation and detection of single photons enable quantum communication, simulation and potentially computing protocols. However scaling to several qubits requires the integration of these functionalities in a single chip. A promising approach to the integration of single-photon sources in a chip is the use of single quantum dots embedded in photonic crystal waveguides or cavities. To this aim, efficient coupling of the emission from single quantum dots in photonic crystal cavities to low-loss ridge-waveguide (RWG) circuits is needed. This is usually hampered by the large mode mismatch between the two systems. In this work the emission of a photonic crystal (PhC) cavity realized on a GaAs/AlGaAs membrane and pumped by quantum dots has been effectively coupled and transferred through a long RWG (~1mm). By continuous tapering in both horizontal and vertical direction, transmission values (fiber-in, fiber-out) around 0.16 and 0.08% for RWG and coupled PhC waveguide-RWG have been achieved, respectively. This corresponds to about 2.8% coupling efficiency between the center of the PhC waveguide and the single-mode output fiber, a value much higher than what is achieved by top collection. It further shows that around 70% of the light in the PhC waveguide is coupled to the RWG. The emission from quantum dots in the cavity has been clearly identified by exciting from the top and collecting the photoluminescence from the cleaved facet of the device 1mm away from the cavity which enables the efficient coupling of single photons to RWG and detector circuits.

We propose using the huge birefringence available in GaAs/AlAs oxidized waveguides to phase-match nonlinear optical conversions in the near- and mid-infrared. Tunable midinfrared radiation can be obtained by difference frequency generation from two tunable near-infrared semiconductor lasers. We measured the transmission spectrum of the AlAs oxide, and demonstrated the birefringence enhancement due to oxidation in a single polarization waveguide.

Using detector tomography, we investigate the detection mechanism in NbN-based superconducting single photon detectors (SSPDs). We demonstrate that the detection probability uniquely depends on a particular linear combination of bias current and energy, for a large variation of bias currents, input energies and detection probabilities, producing a universal detection curve. We obtain this result by studying multiphoton excitations in a nanodetector with a sparsity-based tomographic method that allows factoring out of the optical absorption. We discuss the implication of our model system for the understanding of meander-type SSPDs., Comment: Revised version

The integration of single-photon and photon-number-resolving detectors with single-photon sources and passive circuits is essential to realise fully-functional quantum photonic integrated circuits. We have recently demonstrated the first waveguide single photon detectors (WSPDs)[1] and a polarisation-independent on-chip autocorrelator for the measurement of the second-order correlation function g (2)(t)[2], based on superconducting NbN nanowires on top of a GaAs/AlGaAs ridge waveguide. Here, by exploiting the same ...

For the seismic assessment of existing RC buildings an important question is the reliable appraisal of the in situ concrete strength. This parameter can be performed by resorting to destructive tests (concrete core drilling) properly combined with qualitative information provided by Non-Destructive tests (NDTs). However, there are many factors that influence the results of the experimental tests, and it is difficult to establish whether the value obtained is really representative of the material in situ and if there are alterations which have arisen in time. In the paper, a methodology aimed at the definition of a coefficient called “CDD” is proposed. This coefficient takes into account the effects of the deterioration and alteration of the drilled core, and provides an ideal percentage decrease of the mechanical strength (ΔR) of the concrete core (with respect to the original one), as a function of the compaction degree gc. The proposed methodology was applied to 2 set of samples, including drilled concrete cores and cubic specimens, respectively coming from an existing and a brand new building. The method allows to appraise and critically compare the difference between the strength obtained from drilling tests and the one measured on the specimens sampled during the casting.

A Nth-order (N=1, 2, 3, 4, 5, 6) interferometric autocorrelator based on superconducting nanodetectors is presented. It provides much higher sensitivity as compared to the conventional autocorrelators using all-optical nonlinearities and a temporal resolution of about 20 ps, which is limited by the quasi-particle energy relaxation time in the superconducting films. A semiclassical model is introduced to explain the nonlinear photodetection process. A comparison of sensitivity to conventional autocorrelators is also presented. © 2013 SPIE.

We present our progress in the development of an integrated technology suitable for the photonic quantum information processing, showing the first autocorrelator based on two separated detectors integrated on top of the same ridge waveguide. An efficiency of ~1% at 1300 nm for both detectors and independent of the polarization of the incoming photons, is reported. This ultracompact device enables the on-chip measurement of the second-order correlation function g (2) (τ) . We will further discuss ongoing work on the integration of detectors with single-photon sources.

This work was financially supported by the European Commission through FP7 QUANTIP (Contract No. 244026) We demonstrate an integrated autocorrelator based on two superconducting single-photon detectors patterned on top of a GaAs ridge waveguide. This device enables the on-chip measurement of the second-order intensity correlation function g((2))(tau). A polarization-independent device quantum efficiency in the 1% range is reported, with a timing jitter of 88 ps at 1300 nm. g((2))(tau) measurements of continuous-wave and pulsed laser excitations are demonstrated with no measurable crosstalk within our measurement accuracy. © 2013 OSA. Publisher PDF

The authors develop a theory within the effective-mass approxn. of the 2nd-order susceptibility of a quantum well subject to an applied elec. field. Close to the midgap of the structure it is possible within that approxn. to reduce the normally derived triple sums over subbands to a simple sum over all the optically allowed transitions. In realistic structures, higher-energy transitions play a strong role for quant. results. This strong influence of the higher-energy transitions on the 2nd-order susceptibility has the consequence that it is not generally possible to define a quantum-well susceptibility independent of the structure in which the well is inserted. Numerical results indicate that the quantum wells should not lead to spectacular enhancements of the 2nd-harmonic-generation susceptibility. [on SciFinder (R)]

Progress towards the development of a quantum integrated photonics platform on GaAs will be reported, including on-chip single photon sources, detectors, splitters, couplers and modulators.

The treatment of benign thyroid disease is a topic widely debated, ranging from "Lobectomy" to "Total Thyroidectomy". This study aims to contribute to the thinking on treatment strategies for benign thyroid disease.Thirty five patients underwent surgical treatment following the pre-surgical diagnosis of benign thyroid disease between 2003 and 2005 at the Complex Unit of General and Geriatric Surgery at the Second University of Naples (S.U.N.). In 26 cases total thyroidectomies were performed, in 3 subtotal thyroidectomies, in 6 simple lobectomies.Post-surgical course was optimal in the majority of cases. The large number of total thyroidectomies performed is consistent with the trend favoured by this type of strategy. When backed by FNA, non-radical surgery can be opted with greater confidence for single nodules and when surgical risks are high. The refinement of surgical techniques and directions for the identifying and preparing the recurrent nerve have enabled a radical approach in treating thyroid nodular disease.In our opinion, for a solitary nodule with residual diseased parenchyma we believe total thyroidectomy should be prescribed. If, however, the residual parenchyma is unharmed a lobectomy may be considered. In conclusion, we recommend the individual assessment of each pathology, though we favour total thyroidectomy.

There is much controversy surrounding the treatment of benign breast lesions in young adolescents: on one side the need for surgical treatment and on the other doubts in regard to operating on young patients with a benign disease. Another element sparking the debate is the correlation between the appearance of fibroadenomas and the presence of elevated prolactin levels in the blood.42 patients between the ages of 14 and 21 being treated at the General surgery and Geriatrics Unit of the Department of Gerontology, Geriatrics and Metabolic Diseases at the Second University of Naples between 2001 and 2004. In addition, blood prolactin levels were measured in 24 patients.Only 4.76% of the patients examined (2 cases) had a family history of breast tumours. Out of a total of 42 adolescent patients that were operated on, we detected fibroadenomas in 35 (83.34%), fibrocystic disease in 3 (7.14%), adenosis in 3 patients (7.14%) and a phylloid tumour in 1 (2.38%). Blood prolactin was measured in 24 patients and in 17 cases we detected increased plasmatic levels of this hormone; in addition, anamneses revealed that of these 17 patients, 9 were using oral contraceptives.The most common cause of palpable breast masses in adolescents under 21 years of age are fibroadenomas. The connection to hormonal, genetic and family factors is still unknown, both during the genesis of this pathology and as concerns an increased risk of possible malignant development. The correlation between fibroadenomas and elevated prolactin serum levels still remains controversial today. Various studies, measuring the blood concentration of prolactin in many patients have demonstrated that both elevated blood levels of this hormone and the use of oral contraceptives play a role in the development and growth of benign breast lesions.Fortunately, breast disease is rare in adolescents; these patients do not often develop nodules and where these do occur the vast majority of cases involve benign lesions. A thorough follow-up on patients with nodular breast lesions is thus useful. As concerns the connection between prolactin and fibroadenomas, we also reported interesting data; this represents 70.83% of our subjects.Blood prolactin levels, Fibroadenomas, Surgical treatment.

A plasmonic laser structure coupled to a dielectric waveguide is proposed and investigated by rigorous simulations. Modal characteristics, such as propagation loss and confinement factor were obtained for a wavelength of 1.55 µm. In addition, FDTD (Finite-Difference Time-Domain) simulations were used to calculate the reflectivity from the end facets of the laser structure and also to calculate the coupling between the laser and a dielectric waveguide. Simulations show that a threshold gain of 1796 cm-1 is required to compensate the total loss in a 200 nm wide and 50 µm long laser, which can be achievable at room temperature.

We present the design, the fabrication and the characterization of a tunable one-dimensional (1D) photonic crystal cavity (PCC) etched on two vertically-coupled GaAs nanobeams. A novel fabrication method which prevents their adhesion under capillary forces is introduced. We discuss a design to increase the flexibility of the structure and we demonstrate a large reversible and controllable electromechanical wavelength tuning (> 15 nm) of the cavity modes., 11 pages, 4 figures

Photonic crystal (PhC) cavities made in broadband luminescent material offer attractive possibilities for flexible active devices. The luminescence enables the cavity to operate as an autonomous entity. New applications of this property are demonstrated for cavities made in the InGaAsP underetched semiconductor membrane with embedded InAs Quantum Dots that emit in the range of 1400-1600 nm. Planar photonic crystal membrane nanocavities were released from the parent chip by mechanical nanomanipulation. The released cavity particle could be bonded on an arbitrary surface, which was exploited to make a novel fiber-optic tip sensor with a PhC cavity attached to the tip. A single mode from a short cavity is shown to couple simultaneously to at least three cavity modes of a long cavity, as concluded from level anticrossing data when the small cavity was photothermally tuned. Reconfigurable and movable cavities were created by locally varying the infiltration status by liquid oil near a PhC waveguide or defect cavity. Liquid was displaced locally on a micron scale using capillary force effects or laser-induced evaporation and condensation phenomena.

Efficient sources of indistinguishable single photons are a key resource for various applications in fields like quantum sensing, quantum metrology and quantum information processing. In this contribution we report on single photon generation based on III-V semiconductor quantum dots (QDs). To increase the emission efficiency of single photons, it is essential to tailor the radiative properties of the quantum dot emitters by engineering their photonic environment. We present optimized single photon emitters being based on both micropillar and photonics crystal cavities, for applications in a vertical platform and on-chip in-plane platform, respectively. Electrically driven single photon sources with self assembled semiconductor QDs embedded into GaAs/AlAs micropillar cavities emit on demand net rates of ~35 MHz single photons, thus being well exploitable in quantum key distribution systems. In order to establish also a spatially deterministic fabrication platform, position controlled quantum dots are integrated into p-i-n micropillar cavities and single photon emission of a coupled QD-micropillar diode system is observed. Efficient broadband coupling of single photons into photonic crystal waveguides provides the basis for all on-chip quantum information processing, and an according approach is reported.