Explore local activities

Nicolas Fressengeas

@fresseng 11 yr. ago

MOVPE growth of InGaN on ZnO-buffered Si(111) substrates for solar cells applications

Nicolas Fressengeas

@fresseng 11 yr. ago

Fast photorefractive self-focusing in InP:Fe at infra-red wavelengths: simulations and experimental results

Photorefractive self focusing in InP :Fe semiconductor is analysed experimentally and theoretically at 1.06 and 1.55 µm. We show how the self focusing can be controlled by tuning various parameters. Short response times (10µs) are measured for low intensities (10W/cm²)

Nicolas Fressengeas

@fresseng 11 yr. ago

The theory of photorefractive resonance for localized beams in two-carrier photorefractive systems

This paper extends the existing theory of two carrier photorefractivity resonance, which is generally applied to Iron doped Indium Phosphide (InP:Fe), to the case of low non-harmonic illumination. The space charge field profile is computed, and the variations of its amplitude, width and position are determined as functions of the background intensity. The effect of photorefractive resonance on these quantities is evidenced, contributing to the understanding of published experimental results in InP:Fe.

Nicolas Fressengeas

@fresseng 11 yr. ago

Processing a LiNbO3 crystal fibre for optical applications

We achived the photo-engraving and the test of an optical waveguide by a vortex beam in liNbO3 fibers using the photorefractive effect presents in this material.

Nicolas Fressengeas

@fresseng 11 yr. ago

Engraving and study of an optical waveguide in a LiNbO3:Fe crystal fiber

Nicolas Fressengeas

@fresseng 11 yr. ago

Fast infrared self-focusing in photorefractive InP:Fe

Photorefractive self-focusing temporal dynamic is characterized experimentally in InP:Fe semiconductor and the results are found to be in good agreement with a theoreticalmodel. Short response time (10ìs) aremeasured for relatively low intensities (10W/cm2).

Nicolas Fressengeas

@fresseng 11 yr. ago

Fast infrared self-focusing in photorefractive InP:Fe

Nicolas Fressengeas

@fresseng 11 yr. ago

Cellular based simulation of semiconductors thin films

Nicolas Fressengeas

@fresseng 11 yr. ago

Micro pulling down growth of Fe-doped LiNbO3 crystal fibers for optical waveguide engraving

Nicolas Fressengeas

@fresseng 11 yr. ago

Second Harmonic Generation and related second order Nonlinear Optics

In this lecture, the principles of Optical Second Harmonic Generation in Non Linear second order crystals is explained, along with other second order Non Linearities. Applications are then presented.

Nicolas Fressengeas

@fresseng 11 yr. ago

Outils mathématiques et numériques pour la physique

Nicolas Fressengeas

@fresseng 11 yr. ago

Polarization Optics

After a brief introduction to polarization optics, this lecture reviews the basic formalisms for dealing with it: Jones Calculus for totally polarized light and Stokes parameters associated to Mueller Calculus for partially polarized light.

Nicolas Fressengeas

@fresseng 11 yr. ago

Photorefractive effect in InP:Fe under Gaussian illumination at telecommunication wavelengths

Nicolas Fressengeas

@fresseng 11 yr. ago

Optical Phase Conjugation

Optical Phase Conjugation is a third order non linear peculiar phenomenon occurring in many non linear crystals. Its principles and applications are reviewed.

Nicolas Fressengeas

@fresseng 11 yr. ago

Photorefractivity

This is a basic lecture on photorefractivity: its principle as a low power optical non linearity are shown and applications are reviewed

Nicolas Fressengeas

@fresseng 11 yr. ago

Champs et propagation

Nicolas Fressengeas

@fresseng 11 yr. ago

InterCell: a Software Suite for Rapid Prototyping and Parallel Execution of Fine Grained Applications

InterCell is an open and operational software suite for implementation, code generation and interactive simulation of fine grained parallel computational models. This article describes the software architecture, some use cases from physics and cortical networks as well as first performance measurements.

Nicolas Fressengeas

@fresseng 11 yr. ago

Photorefractive effect in InP:Fe under Gaussian illumination at telecommunication wavelengths

Nicolas Fressengeas

@fresseng 11 yr. ago

InterCell: a Software Suite for Rapid Prototyping and Parallel Execution of Fine Grained Applications

InterCell is an open, operational software suite for implementation, code generation and interactive simulation of fine grained parallel computational models. This article describes the software architecture, some use cases from physics and cortical networks as well as first performance measurements.

Nicolas Fressengeas

@fresseng 11 yr. ago

Optimized sub-wavelength grating mirror design for mid infrared wavelength range

Several subwavelength grating mirrors have been designed for VCSEL application in mid-infrared wavelength range (λ = 2.3 µm). These mirrors are automatically optimized thanks to a global algorithm which maximizes a specially defined quality factor for VCSEL top mirrors. Three different designs based on Si/SiO2, AlGaSb/GaSb and GaAs/AlOx are simulated and exhibit bandwidth as large as 206 nm. Also, the bandwidth is polarisation selective with a TM reflection coefficient higher than 99.9 % while TE coefficient is kept below 90 %. These reflectors present several fabrication solutions with a trade off between technological limitations, tolerances in regard to the fabrication error and mirror quality.