Wavelength Tunable Pulsed Lasers Enabled by a Versatile Metafiber Functioning as Both Saturable Absorber and Filter

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High-efficiency single-photon detection in the microwave domain is a key enabling technology for various quantum applications. However, the extremely low energy of microwave photons presents a fundamental challenge, preventing direct photon-to-charge conversion as achieved in optical systems using semiconductors. Here, we demonstrate continuous microwave photon detection with an efficiency approaching 70% in the single-photon regime. We use a hybrid system comprising a gate-defined double quantum dot (DQD)

Deployment of terahertz communication and spectroscopy systems relies on the availability of low-noise and fast detectors, with plug-and-play capabilities. However, most current technologies are stand-alone, discrete components. They are often slow or susceptible to temperature drifts and require tight beam focusing to maximize the signal-to-noise of the detector. Here, we demonstrate an integrated photonic architecture in thin-film lithium niobate that addresses these challenges by exploiting the electro-o

We present a new fiber-coupled organic scintillator fast neutron detector. Plastic scintillators are used in many applications to detect fast neutrons and gamma rays. The interest in small, fiber-coupled scintillation detectors is in their ability to perform high-resolution neutron flux measurements to ultimately provide multi-physics flux data in research nuclear reactors. Such measurements are planned in the framework of the EURATOM EVEREST project, specifically in the JSI-TRIGA and BME reactors to produc

Quantum emitters, such as quantum dots and organic molecules, are vital components in many modern optical devices, including displays and sensing systems. In the visible spectrum, these emitters are highly efficient in light emission, but their performance declines significantly with decreasing optical gap due to the energy-gap law, limiting their use especially for infrared applications. To overcome this, coupling them with plasmonic particles can significantly enhance light emission by leveraging field co

Clusters and nanocrystals constitute intermediates between molecules and condensed matter. Due to their finite size, clusters have a wide spectrum of applications ranging from building blocks for novel materials to model systems for fundamental investigations about light-matter interactions. Short-wavelength radiation from synchrotron radiation sources and free-electron lasers allows the detailed investigation of their geometric, electronic, and magnetic structure as well as dynamical processes. Conversely,

We propose a device architecture capable of direct quantum coherent electro-optical conversion of microwave-to-optical photons. The hybrid system consists of a planar superconducting microwave circuit coupled to an integrated whispering-gallery-mode microresonator made from an electro-optical material. We show that by exploiting the large vacuum electric field of the planar microwave resonator, electro-optical (vacuum) coupling strengths g(0) as large as similar to 2 pi O(10 - 100) kHz are achievable with c

Purpose – Since pulsed lasers are mainly used in selective laser sintering (SLS) – contrarily to selective laser melting (SLM) – only the exterior of the powder particles is molten while their core stays solid. The purpose of this paper is to investigate the binding mechanism between two particles of titanium powder. Design/methodology/approach – A dedicated experimental setup is used to isolate the particles. They are then irradiated by the laser. SEM micrographs are taken at each step and image analysis i

The correction of field curvature by space or time multiplexing enables the design of a very simple imaging system for mobile device. Here, the optical design is presented and methods to correct the field curvature are discussed. This imaging system can be fabricated with wafer-level processes enabling large-scale and low cost production

Using tunnel junction patterning and double wafer fusion, we demonstrate phase-locked arrays of VCSELs emitting at the 1300 nm waveband. CW powers as high as 10 mW and coherent beams are demonstrated for various array configurations. (C) 2009 Optical Society of America

Subwavelength hole arrays in thin gold films were fabricated in a low-cost and parallel fabrication process on 2" wafers. Polystyrene beads were used as an initial pattern template which is transferred into a thin gold film by sputter etching. Hole arrays with two different periodicities were characterized in optical transmission measurements in air and in liquids of varying refractive index. Despite the conical hole shape and long-range disorder of the arrays, the optical transmission spectra are similar t

Over the past decade a new family of optoelectronic devices has emerged whose performance is enhanced by placing the active device structure inside a Fabry–Perot resonantmicrocavity [P. E. Green, IEEE Spectrum 13 (2002)]. The increased optical field allows photodetectors to be made thinner and therefore faster, while simultaneously increasing the quantum efficiency at the resonant wavelengths. We have demonstrated a variety of resonant cavity enhanced (RCE) photodetectors in compound semiconductors [B. Yang

We report direct absorption spectroscopic detection of ozone at ambient pressure with a pulsed, DFB quantum-cascade laser (QCL) tuned within 1044-1050 cm(-1) by temperature scanning. Wavelength calibration curves were derived from FTIR and CO2 spectra and interpreted with respect to the heat transfer from the heterostructure to the sink. The laser linewidth (similar to0.13 cm(-1) FWHM) was found to decrease with temperature, probably as a result of operation at constant current. Spurious spectral features d

A 3D imager is presented capable of computing the depth map as well as the intensity scale of a given scene. The heart of the system is a two-dimensional array of single photon avalanche diodes fabricated in standard CMOS technology. The diodes exhibit low noise equivalent power, high dynamic range and superior linearity. The 3D imager achieves sub-millimetric precision at depth-of-field of a few meters. It operates using a standard LASER source pulsed at 50MHz with 40mW peak power and requires no mechanica

We report on the growth by metalorganic vapor phase epitaxy of a InGaN/GaN resonant-cavity light emitting diode (RCLED) emitting at 454 nm and incorporating a 12-pair Al0.82In0.18N/GaN distributed Bragg reflector as bottom mirror. A(1-x)In(x)N layers with an Al content around x similar to 0.17 are lattice matched to GaN, thus avoiding strain-related issues in the subsequent active layers while keeping a high refractive index contrast of 7%, comparable to that achievable in the Al0.5Ga0.5N/GaN system. Device

Injection locking of two DFB semiconductors opens new possibilities to generate effective signals for optical sensing, in order to reach better performances. Pure waveforms can be generated with qualities exceeding those obtained using external modulators.

First results and analysis of second harmonic generation with a Nd:YAG laser working in the long pulse, free running mode are presented in this paper. Second harmonic generation conversion efficiencies of up to 17.5% and pulse powers of 162W have been generated with a free running Nd:YAG laser and a KTP non-linear crystal. The conversion efficiency is limited by a saturation effect and optical damage occurring at similar to50 times lower peak intensities than in the Q-switch mode. The saturation and damage

We present a tunable interference filter for infrared and visible light that scans the desired part of the optical spectrum within milliseconds. A single pixel detector measures serially the intensity at selected wavelengths. This concept avoids expensive linear detectors as used for grating spectrometers. The tunable optical interference filter is fabricated by a new porous silicon batch technology using only two photolithography steps. The refractive index of this filter microplate is gradually modulated

An all-fiber phase-modulated master oscillator power amplifier for free-space coherent communication is presented. A distributed-feedback fiber laser at 1.06 μm is used as master oscillator. A novel phase modulator based on a ZnO-coated single-mode fiber modulates the single frequency communication signal. The modulated signal is then amplified in a double-clad doped fiber power amplifier. Up to 1 W cw single-frequency output power, phase modulated at 196 MHz, has been obtained.

For future divertor studies on TCV measurements of electron temperature and density and their spatial gradients along open flux surfaces will be of major interest. A Thomson scattering system is proposed for this purpose, which takes advantage of the good access via horizontal ports on three vertical levels. The modular design of the existing Thomson scattering diagnostic on TCV offers the possibility to modify it for simultaneous measurements in the main plasma and in the divertor region using the same las

Piezoelectric coatings of PbZrxTi1-xO3 (PZT) were deposited on standard telecommunication fibers. The PZT coatings were produced by reactive de magnetron sputtering of metal targets in pure oxygen atmosphere. The deposition was carried out at substrate temperatures between 500 and 600 degrees C. Film thicknesses are in the range of 1300 to 1500 nm. The device structure under investigation is of the Ti/Pt/PZT/Au type. X-ray diffraction (XRD) scanning electron microscopy (SEM), and electrical measurements wer

Wavelength Tunable Pulsed Lasers Enabled by a Versatile Metafiber Functioning as Both Saturable Absorber and Filter

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Tunable high-efficiency microwave photon detector based on a double quantum dot coupled to a superconducting high-impedance cavity

Large-area photonic circuits for terahertz detection and beam profiling

Design and testing of a fiber-coupled fast neutron scintillation detector for low-power research reactors

Theoretical Study of Modified Near-Infrared Light Emission: Quantum Emitters in Plasmonic Nanocavities

Clusters and Nanocrystals

On-chip microwave-to-optical quantum coherent converter based on a superconducting resonator coupled to an electro-optic microresonator

Study of the inter-particle necks in selective laser sintering

Space and time multiplexing for field curvature correction in miniature imaging systems

1.3-mu m Wavelength Coupled VCSEL Arrays Employing Patterned Tunnel Junction

Large area hole arrays fabricated by a templating method for refractive index sensing

High-speed Si resonant cavity enhanced photodetectors and arrays

Ozone detection by differential absorption spectroscopy at ambient pressure with a 9.6 mu m pulsed quantum-cascade laser

Toward a 3-D Camera Based on Single Photon Avalanche Diodes

InGaN/GaN resonant-cavity LED including an AlInN/GaN bragg mirror

Generation of high-quality signals for optical sensing using DFB lasers injection locking

Second harmonic generation with free running Nd : YAG laser

Microspectrometer based on a tunable optical filter of porous silicon

All-fiber phase-modulated master oscillator power amplifier for coherent communication

A Thomson scattering diagnostic for measurements in the divertor region of TCV

PZT coated optical fibers for acousto-optical modulation