A5062233162- Photonic and Optical Devices
- Terahertz technology and applications
- Spectroscopy and Laser Applications
- Semiconductor Quantum Structures and Devices
- Advanced Fiber Laser Technologies
- Superconducting and THz Device Technology
- Microwave Engineering and Waveguides
- Semiconductor Lasers and Optical Devices
- Gyrotron and Vacuum Electronics Research
- Millimeter-Wave Propagation and Modeling
- Laser-Matter Interactions and Applications
- Photorefractive and Nonlinear Optics
- Advanced Photonic Communication Systems
- Sensor Technology and Measurement Systems
- Acoustic Wave Resonator Technologies
- Optical Coatings and Gratings
- Metamaterials and Metasurfaces Applications
- Optical Network Technologies
- Antenna Design and Analysis
- Mechanical and Optical Resonators
- Spectroscopy and Quantum Chemical Studies
- Nonlinear Optical Materials Research
- Thermography and Photoacoustic Techniques
- Surface and Thin Film Phenomena
- Advanced Antenna and Metasurface Technologies
Institut polytechnique de Grenoble
2010-2024
Université Savoie Mont Blanc
2009-2024
Institut de Microélectronique, Electromagnétisme et Photonique
2014-2024
Centre National de la Recherche Scientifique
1995-2024
Université Grenoble Alpes
2018-2024
Physiotherapy New Zealand
2023
EDP Sciences
2020
Institut Français
2020
Los Angeles Harbor College
2001-2013
Total (United Kingdom)
2002
From classical charge transport equations and dipole radiation equations, we derive a simple analytical model for the signal detected in terahertz time-domain spectroscopy using photoconducting antennas. The validity of our is checked by comparison to published calculated results experimental data have measured. This expression depends mostly on carrier lifetime antennas' semiconductor material laser pulse duration. form (THz) allows us separate contribution different parameters. Together...
We present results of 2D real-time imaging terahertz (THz) beam generated by a photoconductive antenna driven femtosecond oscillator. The detector, operating at room temperature, is 320 x 240 array antenna-coupled microbolometers with integrated CMOS read-out electronics delivering 25 images per second. High quality broadband THz beams covering the 0.1-2 range are recorded while maintaining signal-to-noise ratio 10 for detected power as low nW. compactness easy-to-use uncooled camera makes...
A continuous-wave dual-wavelength solid-state microlaser is presented and a technique for regulating the gain competition between two wavelengths proposed, based on angular tilt of laser cavity output mirror. Laser behavior studied balanced emission obtained with power levels as high 200 mW 2 W pump power. Sum frequency mixing demonstrated making source promising Terahertz generation in 0.5-0.7 THz range through difference generation.
Using terahertz time-domain spectroscopy, we report the principal values of absorption coefficients and refractive indices as a function wavelength between 0.5 2.0 THz eight attractive nonlinear crystals: YCOB, BNA, LBO, CSP, AGS, CdSe, ZnO GaP. From these data, calculated coherence length phase-matching conditions associated to emission wave from second-order difference-frequency generation.
Frequency doubling is observed in an aluminum nitride waveguide deposited by dc reactive magnetron sputtering. Phase-matching conditions are obtained tuning the wavelength of optical parametric oscillator pumped a pulsed Nd:YAG laser. The maximum second harmonic generation efficiency for TM0(ω)-TM2(2ω) conversion process and estimated to be around 4×10−8 W−1.
The efficiency of photo-conductive switches, which continue to be used for the generation and detection THz waves, has been overlooked a long time. so far 'optics-dominated' devices are making their way through new emerging fields research that require ultrafast picosecond voltage pulses, as well applications where power is uttermost importance. To address problems, in this article we present novel switch based on 3-dimensional design. In contrast conventional planar designs, our drastically...
We report on the efficient coupling of terahertz (THz) waves into a dielectric waveguide by means diffraction grating engraved at top waveguide. The is made 201-microm-thick high-resistivity silicon wafer. transmission device, measured versus frequency time-domain spectroscopy, shows usual m lines when component THz pulse spectrum satisfies phase-matching condition and coupled experimental data are well modeled with differential electromagnetic method to compute pattern device. dispersion...
The dynamical electrical properties of annealed low-temperature-grown GaAs layers moderately doped with beryllium are studied using photoconductive sampling. Picosecond pulses sampled an interdigitated metal-semiconductor-metal structure. These time-resolved experiments supported by numerical simulation allow us to determine electron and hole mobilities of, respectively, 540 90cm2∕V∕s. We also demonstrate that the free-electron trapping process is saturating under high-optical-density...
A passively Q-switched dual-wavelength solid-state laser is presented. The two wavelengths are emitted by different crystals in order to avoid gain competition, and the synchronization between pulses obtained external triggering of saturable absorber. Sum frequency mixing demonstrated, proving interest this source for terahertz generation 0.3-0.4 THz range through difference generation.
Diffraction gratings can be used to achieve phase matching between the fundamental modes of a slab or confined waveguide. Compared with usual techniques such as quasi-, Čerenkov, and intermodal matching, method here involves spatial harmonics guided electromagnetic field that are generated by corrugated grating. This grating acts simultaneously linear waveguide coupler at both pump harmonic frequencies. Using third harmonic, we report what believe first observation grating-assisted...
Using femtosecond time resolved reflectivity, we have characterized the dynamics of photoinduced generated carriers in a polycrystalline low-temperature-grown GaAs sample. Our measurements are fitted with an analytical expression reliable for low pump power experiments. The sample, which presents no As precipitates, shows ultrafast subpicosecond response together longer picosecond tail that attribute to midgap defect states. Moreover, observed influence surface roughness on differential...
High permittivity SrTiO3 for the realization of all-dielectric metamaterials operating at terahertz frequencies was fabricated. A comparison different processing methods demonstrates that Spark Plasma Sintering is most effective sintering process to yield high density ceramic with permittivity. We compare this two other processes. The fabricated samples are characterized in low frequency and ranges. Their relative permittivities compared a reference single crystal. sample by as role...
We derive the microwave bandwidth of ultrafast optoelectronic samplers based on photoconducting switches, using a simple analytical model. The validity this model is checked by measuring semi-intrinsic and low-temperature-grown GaAs photoswitches. such devices limited response time both semiconductor material electrical circuit. behave as low-pass filters exhibiting -60 dB/decade slope.
This article reports a novel 3-D imaging approach for remote, nondestructive material inspection at depth. The is based on frequency-modulated continuous-wave (FMCW) radar system operating in the 75-110-GHz frequency band. Time-domain spectroscopy (TDS) measurements demonstrate that such band has manage-able attenuation levels centimeter-long materials, thereby offering an advantageous resolution-versus-measurement-depth tradeoff compared with higher frequencies. proposed setup includes long...
Using terahertz (THz) time-domain spectroscopy, we study the coupling of THz waves into a silicon waveguide by means grating coupler. We vary efficiency coefficient for selected frequencies up to 20% in amplitude (40% intensity) generating photocarriers material through illumination with white light. The experimental data are well fitted using differential method model diffraction.
We present a study of the mixing radio frequency (RF) signal and modulated optical beam, resulting from beating two CW lasers, using photoconductive switch as mixer. The process generates sideband frequencies in RF transmitted signal. theoretical analysis gives performance device versus its main physical parameters. device, if made ultrafast semiconductors, can handle or/and up to 100 GHz. When dc biased, serves an optoelectronic generator Our is experimentally validated range 40 GHz...
Terahertz applications have been extensively studied during the last decade since they allow not only increasing bandwidth of telecom systems but also detection many organic molecules in solid and liquid phase, including hazardous materials such as explosives. In this contribution, we present a device that allows generating frequencies domain through heterodyning signals emitted by two distributed feedback lasers made ion exchange on erbium-ytterbium co-doped glass. Thanks to intrinsic...
In this study, we aimed to develop high permittivity TiO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> ceramics ideal for the fabrication of All-Dielectric Metamaterials operational in terahertz frequency. ceramic pellets are fabricated from a commercial powder. A comparative analysis was conducted between Spark Plasma Sintering (SPS) and conventional sintering process. Characterizations were then carried out range 0.2 1.4 THz using...
This paper describes a new computational method for recursive least squares (RLS) algorithm. It is well known that the initial values computing RLS estimates should be chosen to guarantee existence of at each step, covariance matrix may affect convergence rate, and blow-up phenomenon (infinite increase matrix) can appear. Much research has focused on these problems, but heavy computations different specific design parameters result from most common solutions. We propose an alternative simple...