Papers by Horacio Failache
Communication orale 30 mn présentée par D Blochaudience de la conférence : environ 90 participant... more Communication orale 30 mn présentée par D Blochaudience de la conférence : environ 90 participantsInternational audienc
2021 IEEE 12th Latin America Symposium on Circuits and System (LASCAS)
This paper presents the design, manufacture, and testing of a trans-impedance amplifier for a min... more This paper presents the design, manufacture, and testing of a trans-impedance amplifier for a miniaturized saturated absorption spectrometer. The amplifier has a bandwidth of 32 kHz, a dc gain of 80.3 dB-Ohm, and an output voltage swing of 4.84 Vpp. The device can handle an input optical power up to 800 µW, where the photodetection electronics have a Noise Equivalent Power of 0.3 pW/√Hz. The circuit board has a size of 27 x 27 mm2. Signals acquired with our miniaturized device perfectly match those recorded with a commercial tabletop optical setup.
HardwareX, 2021
Faced with a global pandemic such as the one triggered by the SARS-CoV-2 virus, the medical suppl... more Faced with a global pandemic such as the one triggered by the SARS-CoV-2 virus, the medical supply chain has been highly demanded. An item in which this manifested itself more clearly, are the N95 masks, designed to be disposable items, in many cases they have had to be reused. In these emergency conditions, it was necessary to apply an effective and safe method that can be used locally. Here a device for disinfection by ultraviolet C light was developed that allows irradiating N95 masks with a known and reproducible dose. Thus being able to apply a safe and effective disinfection method according to existing information. The use of a common model of UV-C lamps and the simple construction of the device allows it to be built at low cost and with widely available materials. The effectiveness of the device was demonstrated against an enveloped RNA virus, characteristics shared with the virus that causes COVID19, being capable of reducing the viral load by 4 orders of magnitude.
When a vapour is confined, the collisions to the confinement wall usually cause a broadening of t... more When a vapour is confined, the collisions to the confinement wall usually cause a broadening of the transitions. However velocity selective processes and the coherent enhancement of some transient contributions can lead to sub-Doppler contributions because of the confinement. In the optical range, this had been demonstrated for a one-dimensional confinement with micro- or nano-cells of a small thickness. A two-dimensional confinement in a hollow fiber had shown sub-Doppler contributions, but only equivalent to macrosocpic non linear saturated absorption spectroscopy. Here, we describe experiments showing that a thermal vapor confined in a three-dimensional nanostructure can exhibit sub-Doppler features in a linear regime. We perform reflection spectroscopy on a Cs vapour cell whose window is covered with a thin opal film (typically, 10 or 20 layers of ~ 1µm or 400 nm diameter spheres). We demonstrate, both experimentally and through a modeling that the sub-Doppler structures observe...
Supporting files for the article "LUCIA: An open source device for disinfection of N95 masks... more Supporting files for the article "LUCIA: An open source device for disinfection of N95 masks using UV-C radiation".
Dans le prolongement de nos investigations systematiques du comportement des vapeurs resonnantes ... more Dans le prolongement de nos investigations systematiques du comportement des vapeurs resonnantes confinees dans des micro- ou nano-cellules – confinement a une dimension-, nous commencons a etudier le comportement d'une vapeur confinee, a 3 dimensions, dans les regions interstitielles d'une opale. Des experiences preliminaires de reflexion selective sur la raie de resonance du cesium montrent des formes de raie sous-Doppler, evocatrices d'un retrecissement de type Dicke dans le domaine optique
Journal of the Korean Physical Society, 2000
ABSTRACT
Journal of Applied Physics, 2019
We have developed a method to measure the characteristic interstice size of transparent porous di... more We have developed a method to measure the characteristic interstice size of transparent porous dielectric media. The method is based upon the observation of the transient decay of alkali atoms contained in the medium pores and excited to a sufficiently long-lived state. We present a simple model describing the dependence of the decay transients on the distance L traveled by the atoms between interstice walls. Fitting of the observed transient data to the model predictions allows the determination of L. The method is tested with two well-characterized micrometric thin cells and used to measure the characteristic interstice size of several porous glass samples.
Http Www Theses Fr, 1999
Dans ce memoire, on decrit des experiences qui mettent en evidence une resonance dans l'inter... more Dans ce memoire, on decrit des experiences qui mettent en evidence une resonance dans l'interaction de surface a longue portee, du type de van der waals (vdw), entre un atome et une paroi dielectrique. Le processus elementaire a l'origine de cette interaction est un couplage entre une emission virtuelle de l'atome excite et l'excitation virtuelle d'un mode electromagnetique de surface (polariton de surface). Selon le couplage entre la transition virtuelle et le polariton de surface, ce type d'interaction permet d'avoir, pour la partie dispersive du couplage, un potentiel de vdw exalte par rapport a celui obtenu dans le cas d'une surface conductrice ideale, et avec un potentiel vdw qui devient eventuellement repulsif. Les experiences decrites ont ete faites sur les niveaux cs*(6d 3 / 2), rb*(6 d 3 / 2) et rb*(6d 5 / 2) et avec les dielectriques : saphir (al 2o 3) (avec deux orientations differentes de l'axe de birefringence), yag (y 3al 5o 1 2) et silice vitreuse. Les niveaux atomiques mentionnes possedent tous une transition dipolaire en emission vers 12 m, domaine ou il existe un polariton de surface pour le saphir et le yag. Les mesures experimentales montrent qu'il existe, notamment pour le cas cs(6d 3 / 2)-saphir c, une force de vdw repulsive. On a aussi etudie l'effet de la birefringence du milieu dielectrique et montre le caractere critique de l'orientation cristalline pour la resonance de l'interaction. La technique spectroscopique utilise a ete la reflexion selective qui permet de sonder des atomes a une fraction de longueur d'onde ( 100 nm) de la paroi. Cette technique a du etre ici generalisee au cas d'une transition entre niveaux excites. Par ailleurs, a titre de reference spectroscopique pour des atomes libres, on a evalue l'elargissement et le deplacement collisionnel par technique d'absorption saturee sur la transition cs : 6p 1 / 2 6d 3 / 2 (876 nm).
2003 European Quantum Electronics Conference. EQEC 2003 (IEEE Cat No.03TH8665), 2003
ABSTRACT This reports on the surface attraction exerted onto Cs(8P), as measured through the sele... more ABSTRACT This reports on the surface attraction exerted onto Cs(8P), as measured through the selective reflection spectroscopy (SR) technique via a one- photon excitation at 388 nm from the ground state. In a series of experiments on the Cs (6S12/-8P32/) transition in front of a sapphire surface, the accuracy in the van der Waals evaluation, and with an improved fitting method, should be on the order of 10%. Further developments, expected to be reported too, concern the fine structure component Cs (6S12/-8P32/) , along with a study of SR spectroscopy at various interfaces.
Technical Digest. 1998 EQEC. European Quantum Electronics Conference (Cat. No.98TH8326)
Conference Digest. 2000 International Quantum Electronics Conference (Cat. No.00TH8504)
ABSTRACT The topic of quantum cavity electrodynamics is to describe the coupling between the fluc... more ABSTRACT The topic of quantum cavity electrodynamics is to describe the coupling between the fluctuations of an atomic system and the vacuum e.m. field, when special boundary conditions are imposed by a "cavity" to the vacuum field. A realistic description of these boundary conditions is hence of crucial importance. For such a purpose, the unavoidable dispersive spectral properties of any material cavity cannot be ignored when dealing with (temporal) fluctuations. For these reasons, we have embarked on an (experimental) analysis of the resonant long-range coupling between atomic excitation and the surface modes of a cavity (most often restricted to a simple wall, i.e. a flat open cavity). In our present investigations, we are concerned with the exploration of the dissipative counterpart of the resonant atom-surface van der Waals coupling.
Proceedings of 1995 IEEE Instrumentation and Measurement Technology Conference - IMTC '95
This instrument has been developed to measure in real time the wavelength of a continuous laser b... more This instrument has been developed to measure in real time the wavelength of a continuous laser beam with a precision of less than one part in 107. The optic is based on a Kowalski interferometer. The measurement time is 8 seconds and the minimum optical input power needed is 0.5 mW. The measurable wavelength range is 600-1000 nm
2003 European Quantum Electronics Conference. EQEC 2003 (IEEE Cat No.03TH8665), 2003
ABSTRACT Analysis of the data of FM SR lineshapes using a fitting method that simultaneously acco... more ABSTRACT Analysis of the data of FM SR lineshapes using a fitting method that simultaneously accounts for the dispersive and the dissipative effects of the resonant coupling. In the theoretical model, two dimensionless parameters A and B describe the overall z-3 coupling. A=2k3C3/γ0 represents the strength of the vW attraction (γ0, homogeneous linewidth) and B = k3Γ (k = ω0/c with ω0 the frequency of the probed transition in the free space) is for the modified decay rate, with the resonantly-enhanced transition width defined by:γ(z) = γ0(1+Γ/z3). The experiments are performed on Cs (6D32/) interacting with a sapphire surface with its c-axis parallel to the surface. Fits are carried out for the two hyperfine components (F = 3 and F = 4) of the probed transition 6P12/ → 6D32/, and for different values of the Cs temperature. In comparison, present report deals with a situation when the two parameters A and B are comparable, as due to the detuning of the sapphire polariton resonance with the birefringence orientation axis: indeed, for a c-axis parallel to the sapphire window, the atomic de-excitation channel is close to the center of the surface resonance, and this tends to maximize the dissipative effects, while the associated dispersive effect is no longer the dominant one.
Latin America Optics and Photonics Conference, 2010
ABSTRACT We analyze the multi-zone coherent population trapping spectroscopy of alkali-vapor atom... more ABSTRACT We analyze the multi-zone coherent population trapping spectroscopy of alkali-vapor atoms interacting with a laser beam split into several parallel narrow light sheets. We show that the spectroscopic signal is largely insensitive to intensity broadening.
2007 Quantum Electronics and Laser Science Conference, 2007
Coherent population trapping resonances in pure alkaline micrometric thin cells are considered as... more Coherent population trapping resonances in pure alkaline micrometric thin cells are considered as an interesting alternative for the development of miniaturized atomic frequency references. Theoretical and experimental results are presented.
Physical Review A, 2010
In view of application to a miniaturized spectroscopy system, we consider an optical setup that s... more In view of application to a miniaturized spectroscopy system, we consider an optical setup that splits a laser beam into several parallel narrow light sheets allowing an effective beam expansion and consequently longer atom-light interaction times. We analyze the multizone coherent population trapping (MZCPT) spectroscopy of alkali-metal-vapor atoms, without buffer gas, in the presence of a split light beam. We show that the MZCPT signal is largely insensitive to intensity broadening. Experimentally observed spectra are in qualitative agreement with the predictions of a simplified model that describes each spectrum as an integral over the atomic velocity distribution of Ramsey multizone spectra.
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Papers by Horacio Failache