JEOS:RP - Journal of the European Optical Society Rapid publications
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Application of Lippmann interference photography to data storage
Get PDFLippmann's interference photography is an elegant process to record coloured images in the volume of a sensitive material. We propose to use this technique for wavelength multiplexed data storage in a page-oriented approach. Using computer simulations, we demonstrate that the capacities reached with this technique are similar to those reached by volume holographic data storage
Bose-Einstein condensation in semiconductors: myth or reality?
Get PDFBose-Einstein condensation, predicted for a gas of non interacting bosons in 1924 by Einstein, has been demonstrated for the first time in 1995 in a dilute gas of rubidium atoms at temperatures below 10^–6 K. In this work, it is shown that Bose-Einstein condensation can be achieved at around 15 – 20 K in a solid state system by using microcavity polaritons, which are composite bosons of mass ten billion times lighter than that of rubidium atoms
Wavelength dependence of polarimetric and phase-shift characterization of a liquid crystal on silicon display
Get PDFWe present a full characterization of a liquid-crystal-on-silicon (LCoS) display, including a polarimetric analysis based on the Mueller-Stokes formalism, and a phase shift modulation calibration. Results for different wavelengths are compared. The goal of this work is two fold. On one side, previous papers dealing with the illumination wavelength 633 nm have shown that LCoS produce a non negligible amount of depolarized light. This may have a negative impact in certain applications. Here we want to establish how this depolarization varies with the wavelength. On the other side, to use the LCoS as a spatial light modulator (SLM) we need to obtain optimal configurations enabling for phase-only or for amplitude-only modulation. Here we show how phase-only modulation is obtained, and how it evolves with the wavelength. In principle, for shorter wavelengths the phase modulation depth increases and the energy throughput may also be increased. However, these phase-only configurations may be partially degraded by the presence of depolarization at certain gray levels. Thus, the Mueller-Stokes formalism is necessary to get a full picture of the performance exhibited by the LCoS at each wavelengt
Solid state atomic processors for light
Get PDFThis paper is devoted to optics in rare earth ion doped crystal at low temperature. In cryogenic conditions, interesting features come from absorption rather than from transparency. The optical transition linewidth is considerably reduced, which also corresponds to a strong increase of quantum state lifetime. Linewidth narrowing leads to signal processing applications. Specific use for RADAR warning receivers is considered here. Then the quantum lifetime extension is illustrated by coherent transient processes that represent necessary experimental steps on the way to quantum information research
High-temperature type IIa gratings in 12-ring photonic crystal fibre with germanosilicate core
Get PDFThe inscription of efficient Bragg gratings (>20 dB) in 12-ring photonic crystal fibre with a germanosilicate doped core without the need for hydrogen loading using 193 nm is demonstrated. We show the characteristic rollover from type I grating to type IIa – the first observation of a type IIa grating in structured optical fibre. The type IIa grating is shown to survive up to 700°C before any degradation in transmission or reflection takes place
Spectral resolution of optical filters based on diffractive optical elements with non-uniform illumination
Get PDFWe study the transmission coefficient and the spectral resolution of
optical filters based on a diffractive optical element (DOE), with a
collimating lens, input and output fibers. We limit our study to
filters that can be analyzed with a scalar (i.e., Fourier-optical)
formalism, and specify requirements that the filter geometry has to
satisfy for this formalism to give an accurate description. Finally,
we study the trade-off between power loss and spectral resolution in DOE-based filters
Estimation precision of degree of polarization in the presence of signal-dependent and additive Poisson noises
Get PDFWe address precision of estimation of the degree of polarization (DOP) from the orthogonal state contrast image (OSCI) in the presence of both signal-dependent Poisson noise due to useful signal, and additive Poisson noise due to dark current and / or background light. We determine the Cramer Rao Lower Bound and deduce from it figures of merit for DOP estimation. In particular, we show that the additive Poisson noise has larger influence on DOP estimation than on intensity estimation when light is highly polarized
Progress towards lightning control using lasers
Get PDFLightning research needs on-demand lightning strikes, because of the random character of natural lightning. Lasers have been proposed as alternatives to the current technique using rocket-pulled wires, because they would expectedly provide more flexibility. However, high-energy, nanosecond lasers cannot provide long connected plasma channels. In contrast, we recently reported the triggering of electric events in thunderclouds using ultrashort laser pulses. Further improvements of the laser pulse sequence and experiment geometry are discussed
Analytic expressions and approximations for the on-axis, aberration-free Rayleigh and Debye integral in the case of focusing fields on a circular aperture
Get PDFWe present a derivation of the analytic result for on-axis field values of the Rayleigh diffraction integral, a result that was originally presented in a paper by Osterberg and Smith (1961). The method on which our derivation is based is then applied to other diffraction integrals used in acoustics and optics, e.g., the far-field Rayleigh integral, the Debye integral and the separate near-field part of the Rayleigh integral. Having available our on-axis analytic or semi-analytic solutions for these various cases, we compare the various integrals for wave numbers k pertaining to low-frequency acoustic applications all the way up to high-frequency optical applications. Our analytic results are compared to numerical results presented in the literature
Transmission coefficient of a one-dimensional layered medium from a light-path sum
No full textThe transmission coefficient for the amplitude of an electromagnetic field that propagates through a one-dimensional N-layer medium is obtained from summing the coefficients that belong to the individual transmitted light-paths. The medium does not have to be periodic; the layers can have arbitrary physical lengths and arbitrary field response parameters. As compared to the traditional transfer-matrix derivation for the transmission coefficient, the sum-over-all-paths derivation results in a transparent representation that reveals that the presence of the medium can effectively be described as a self-interaction of the field