Abstract Coherent imaging in the THz range promises to exploit peculiar capabilities of these wavelengths penetrate common materials like plastics, ceramics, paper or clothes with potential breakthroughs non-destructive inspection and quality control, homeland security biomedical applications. Up now, however, coherent has been limited by time-consuming raster scanning, point-like detection schemes lack adequate sources. Here, we demonstrate real-time digital holography (DH) at frequencies...

We review recent achievements in the field of nanoscale nonlinear AlGaAs photonics based on all-dielectric optical antennas. After discussing motivation and main technological challenges for development an monolithic platform χ(2) nanophotonics, we present numerical experimental investigations second-order response physical reasons high efficiency interactions nano-antennas. In particular, emphasize role dipolar resonances at fundamental frequency multipolar second harmonic wavelength. also...

Manipulating light at the nanoscale by means of dielectric nanoantennas recently received renewed attention thanks to development key enabling fabrication tools in semiconductor technology, combined with extremely low losses exhibited dielectrics optical regime. Nanostructures based on III–V type semiconductors, characterized an intrinsic broken symmetry down a single elementary cell, has already demonstrated remarkable nonlinear conversion efficiencies scales well below operating...

We report the heterodyne detection and phase locking of a 2.5 THz quantum cascade laser (QCL) using terahertz frequency comb generated in GaAs photomixer femtosecond fiber laser. With 10 mW emitted by QCL, phase-locked signal at intermediate yields 80 dB signal-to-noise ratio bandwidth 1 Hz.

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We present an optomechanical method for locally measuring the rheological properties of complex fluids in ultra-high frequency range (UHF). A mechanical disk microscale volume is used as oscillating probe that monitors a liquid at rest, while oscillation optomechanically transduced. An analytical model fluid-structure interactions to deduce liquid. This calibrated on water, which despite pronounced compressibility effects remains Newtonian over explored range. In contrast, 1-decanol exhibits...

Les photons intriqués forment une ressource précieuse pour la distribution quantique de clés et l’implémentation réseaux quantiques flexibles. Cet article présente les dernières avancées réalisées avec des sources AlGaAs intégrées, exploitant fluorescence paramétrique générer en polarisation ou énergietemps. Ces dispositifs combinent large bande spectrale, brillance élevée forte intégrabilité, permettant progresser vers le déploiement hors-laboratoire communications quantiques.

We study the formation dynamics of a spontaneous ferromagnetic order in single self-assembled CdMnTe quantum dots. By measuring time-resolved photoluminescence, we determine times for QDs with Mn ion contents x varying from 0.01 to 0.2. At low these are orders magnitude longer than exciton spin relaxation evaluated decay photoluminescence circular polarization. This allows us conclude that direction magnetization is determined by momentary fluctuation rather resulting an optical orientation....

We examine, in the time domain, influence of Au antenna arrays (i.e., metasurfaces) on thin films near-infrared PbS nanocrystals that mutually interact via Förster resonance energy transfer (FRET). While geometry and optical properties have a direct sometimes spectacular impact transient photoluminescence spectra emitters, we experimentally show decay rates at any given wavelength are remarkably similar for all samples. This observation is stark contrast with textbook case individual...

We report the direct proof of parametric amplification in a semiconductor waveguide. Thanks to low propagation losses and high nonlinear efficiency, we amplified an input signal at 2 μm selectively oxidized GaAs/AlAs multilayer waveguide through down conversion pump 1 μm. The 4.5% single-pass gain measured for 30 mW cw is compatible with oscillation, provided that distributed concentrated are further reduced.

We demonstrate a coherent imaging system based on terahertz (THz) frequency quantum cascade laser (QCL) phase-locked to near-infrared fs-laser comb. The phase locking enables electro-optic sampling of the continuous-wave radiation emitted by QCL through generation heterodyne beat-note signal. use this signal raster scan using emitting at 2.5 THz. At detection noise floor our is 3 pW/Hz and long-term stability <3 degrees/h, limited mechanical apparatus.

The use of a high-electron mobility semiconductor nanowire as transistor channel has recently allowed the extension spectral coverage THz field-effect detectors up to 1.5 THz. In this report, we demonstrate efficient operation detector based on at much higher frequency, 2.8 THz, with responsivity ≈5 V/W in bandwidth ≈100 kHz, thus proving full potential such approach for detection quantum cascade lasers. Finally, sensing system is exploited perform raster scan transmission imaging, high...

We report on the experimental observation of quasi-phase matching in a homogeneous waveguide. By fabricating monolithic snake-shaped suspended AlGaAs nanowire (001) GaAs wafer, we demonstrate unraveled version χ(2) whispering-gallery-mode microdisk, obtaining second-harmonic generation optical telecom wavelength range. With radius curvature 50 μm and four spatial oscillations along (110) average direction, splitting spectrum occurs around phase-matching corresponding straight This splitting,...

We report on the evidence of saturation effects in a rotational transition CH3OH around 2.5 THz, induced by free-running continuous-wave quantum cascade laser (QCL). The QCL emission is used for direct-absorption spectroscopy experiments, allowing to study dependence absorption coefficient gas pressure and intensity. A intensity 25 μW/mm2, 17 μbar, measured. This result represents initial step towards implementation QCL-based high-resolution sub-Doppler THz spectroscopy, which expected...

Mid-infrared digital holography based on CO2 lasers has proven to be a powerful coherent imaging technique due reduced sensitivity mechanical vibrations, increased field of view, high optical power, and possible vision through scattering media, e.g., smoke. Here we demonstrate similar more compact holographic system an external cavity quantum cascade laser emitting at 8 μm. Such setup, which includes highly sensitive microbolometric camera, allows the acquisition speckle holograms objects,...

We have designed and fabricated a set of AlGaAs multilayer waveguides, which can serve as source entangled photons at 1.55μm through parametric fluorescence. In our scheme two counterpropagating, orthogonally polarized signal/idler modes are nonlinearly generated by pump wave impinging on the upper surface waveguide. To check compliance with design specifications phase-matching wavelength gain, we systematically measured effective indices surface-emitting second-harmonic generation,...

We report on the realization and characterization of two different designs for resonant THz cavities, based wire-grid polarizers as input/output couplers, injected by a continuous-wave quantum cascade laser (QCL) emitting at 2.55 THz. A comparison between measured resonators parameters expected theoretical values is reported. With achieved quality factor Q ≈ 2.5 × 10(5), these cavities show peaks narrow few MHz, comparable with typical Doppler linewidth molecular transitions slightly broader...

Surface periodic poling of congruent lithium niobate was performed with the aid photolithographically defined silica masks. The latter helped improving control duty cycle in domain poling, 50:50 mark-to-space ratios. role ascertained by numerically solving Poisson equation.

In this Letter, we report on the fabrication and characterization of a monolithic III-V semiconductor photonic chip, designed to perform nonlinear parametric optical processes for frequency conversion non-classical state generation. This chip co-integrates an AlGaAs microdisk that is evanescently coupled two distinct suspended waveguides light injection collection around 1600 nm 800 nm, respectively. Quasi-phase matching provided by resonator geometry material symmetry, resonant field...

Efficient parametric fluorescence is obtained from a pump wavelength λ=1.06μm in low-loss, form-birefringent GaAs∕AlOx waveguides. Besides showing 1μm wide tuning range and the onset of amplification regime for continuous-wave levels around 50mW, an 8% gain determined. This highest figure reported to date semiconductor waveguides, confirms waveguides as candidate integrated optical source.

A spontaneous emission extraction efficiency greater than 50% is observed in a GaAs/AlGaAs quantum well structure grown on the subwavelength-sized ridge top facet of V-grooved substrate by means photoluminescence study. This an about 20 times higher that similar flat substrate. It demonstrated both experimentally and theoretically high result efficient conversion evanescent waves into propagating air through constructive coupling generated two sidewall facets total internal reflection.

We present the stabilization of terahertz (THz) quantum cascade lasers (QCLs) to a harmonic repetition rate femtosecond fiber lasers. The technique that we have developed is 1) inherently broadband, i.e., it allows virtually any THz QCL regardless its emission frequency, and 2) can be implemented using different detection techniques such as electrooptic or photoconductive detection. Using detection, demonstrate phase locking 2.5-THz QCL, producing an RF beatnote with 70 dB dynamic range in...

Due to adjustable modal birefringence, suspended AlGaAs optical waveguides with submicron transverse sections can support phase-matched frequency mixing in the whole material transparency range, even close bandgap, by tuning width-to-height ratio. Furthermore, their single-pass conversion efficiency is potentially huge, thanks extreme confinement of interacting modes highly nonlinear and high-refractive-index core, scattering losses lower than selectively oxidized or quasi-phase-matched...