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Nicolas Fressengeas

@fresseng · 10 years ago

Cellular based simulation of semiconductors thin films

Nicolas Fressengeas

@fresseng · 10 years ago

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

Nicolas Fressengeas

@fresseng · 10 years 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 · 10 years ago

Outils mathématiques et numériques pour la physique

Nicolas Fressengeas

@fresseng · 10 years 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 · 10 years ago

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

Nicolas Fressengeas

@fresseng · 10 years 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 · 10 years 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 · 10 years ago

Champs et propagation

Nicolas Fressengeas

@fresseng · 10 years 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 · 10 years ago

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

Nicolas Fressengeas

@fresseng · 10 years 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 · 10 years 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.

Nicolas Fressengeas

@fresseng · 10 years ago

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

We present the design of a sub-wavelength grating mirror optimized for integration in mid-IR VCSEL. The definition of a quality factor adapted to VCSEL requirements and maximized by an optimization algorithm allowed us to obtain a polarization selective and high reflectivity structure showing several percent of tolerance. The design of the SGM mirror can easily be adapted to the technological constraints of the manufacturers by adjusting the limitations defined for the automated optimization process. Indeed, the comparison between different technological constraints shows that a better accuracy of the etching process results in an increase of the quality of the mirror.

Nicolas Fressengeas

@fresseng · 10 years ago

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

Several designs of sub-wavelength grating mirrors adapted to mid-infrared operation are reported with several percents of tolerance for the grating fabrication. These designs have been automatically optimized by the use of a genetic-based algorithm to maximize a quality factor defined to meet the requirements of a VCSEL cavity mirror. These mirrors are devoted to an integration in VCSEL operating near λ=2.3 µm, with a large bandwidth, very high reflectivity coefficient for transverse magnetic mode only, polarization selectivity and a thickness as low as 2 µm.

Nicolas Fressengeas

@fresseng · 10 years ago

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

Nicolas Fressengeas

@fresseng · 10 years ago

Optimized subwavelength grating mirror design for mid-infrared wavelength range

Nicolas Fressengeas

@fresseng · 10 years ago

Optimized GaAs High Contrast Grating Design and Fabrication for Mid-infrared Application at 2.3 μm

A GaAs high contrast grating design has been optimized for a mid-infrared VCSEL application through the use of an optimization algorithm. Reflection spectra of an experimental grating with dimensions within the computed tolerances are in a correct agreement with the simulations.

Nicolas Fressengeas

@fresseng · 10 years ago

Experimental control of steady state photorefractive self-focusing in InP:Fe at infrared wavelengths

This paper reports an experimental study of the self-focusing process in iron doped indium phosphide at an 1.06 micron wavelength, identifying the influence of temperature, beam intensity and background illumination \RefereeOne{for two different iron dopings}. We point out that the iron ionization ratio is at the origin of different qualitative behavior previously reported and we show that it is possible to reproduce the said behaviors in the same crystal by applying a uniform illumination, allowing their eventual control for dynamic wave-guiding.

Nicolas Fressengeas

@fresseng · 10 years ago

Robust design of subwavelength grating mirror for mid-infrared VCSEL application

We present the design of a Si/Si3N4 subwavelength grating mirror optimized for an integration in mid-infrared VCSEL. The definition of a quality factor adapted to VCSEL requirements and maximized by an optimization algorithm allowed us to obtain a polarization selective and high reflectivity structure. The robustness with respect to fabrication error has been enhanced thanks to a precise study of the grating dimension tolerances.

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