Measurements of the vacuum-ultraviolet (<80-nm) radiation produced by intense ultraviolet (248-nm) irradiation (1015–1016 W/cm2) of rare gases have revealed the copious presence of both harmonic radiation and fluorescence from excited levels. The highest harmonic observed was the seventeenth (14.6 nm) in Ne, the shortest wavelength ever produced by that means. Strong fluorescence was seen from ions of Ar, Kr, and Xe, with the shortest wavelengths observed being below 12 nm. Furthermore, radiation from inner-shell excited configurations in Xe, specifically the 4d95s5p → 4d105s manifold of Xe7+ at ~17.7 nm, was detected. These experimental findings, in alliance with other studies concerning multielectron processes, give evidence for a role of electron correlations in a direct nonlinear process of inner-shell excitation.

Studies of multiphoton production of vacuum-ultraviolet radiation in the rare gases

Diffraction characteristics of general dielectric planar (slab) gratings and surface-relief (corrugated) gratings are reviewed. Applications to laser-beam deflection, guidance, modulation, coupling, filtering, wavefront reconstruction, and distributed feedback in the fields of acoustooptics, integrated optics, holography, and spectral analysis are discussed. An exact formulation of the grating diffraction problem without approximations (rigorous coupled-wave theory developed by the authors) is presented. The method of solution is in terms of state variables and this is presented in detail. Then, using a series of fundamental assumptions, this rigorous theory is shown to reduce to the various existing approximate theories in the appropriate limits. The effects of these fundamental assumptions in the approximate theories are quantified and discussed.

Analysis and applications of optical diffraction by gratings

The real-time information processing and manipulation of electromagnetic waves using nonlinear Qptical techniques has resulted in a myriad of new applications in diverse fields such as quantum electronics, image processing, optical computing, adaptive optics, and nonlinear spectroscopy. In this paper, we review and explore the field, provide a historical perspective, analyze several of the nonlinear interactions useful for the generation of phase-conjugate replicas, and conclude with a brief survey of potential applications and suitable nonlinear media.

Nonlinear Optical Phase Conjugation

Two-dimensional spatial light modulators (SLMs) modulate one of the properties of an optical wavefront (amplitude, phase, polarization) as a function of two spatial dimensions and time in response to information-bearing control signals that may be either optical or electrical. These devices form a critical part of optical information processing systems, serving as input transducers as well as performing several basic processing operations on optical wavefronts. A tutorial overview of the 2-D SLMs is given. their applications are outlined, a classification scheme for them is given, and major types of SLMs that are under active development are described. >

Two-dimensional spatial light modulators: a tutorial

The photorefractive effect—a review

The polarization properties of diffraction from volume phase gratings in photorefractive sillenite crystals such as bismuth silicon oxide (Bi12SiO20), bismuth germanium oxide (Bi12GeO20), and bismuth titanium oxide (Bi12TiO20) are strongly modified by the presence of concomitant natural optical activity and electric-field-induced linear birefringence. A set of coupled-wave equations that characterize the Bragg regime has been derived for the 〈110〉 and the 〈001〉 crystallographic orientations typically employed in volume holographic storage and multiwave-mixing applications. The predicted anisotropic behavior of the grating diffraction is experimentally confirmed, and a significant efficiency improvement is shown to occur for proper choice of the operating mode and the probe beam polarization in a given configuration.

Polarization properties of photorefractive diffraction in electrooptic and optically active sillenite crystals (Bragg regime)

Reference EPFL-ARTICLE-158578doi:10.1364/AO.22.003665View record in Web of Science Record created on 2010-11-25, modified on 2017-07-31

/pdf/photorefractive-incoherent-to-coherent-optical-converter-2fiagz18s1.pdf

Photorefractive incoherent-to-coherent optical converter

Volume holographic storage in photorefractive Bit 2S i020 (BSO) crystals is utilized to perform dynamic incoherent-to-coherent image conversion by means of selective spatial erasure of a uniform grating with white (or quasi-monochromatic) light. Physical characterization of device performance is de-scribed, with emphasis on resolution, sensitivity, and temporal response. The photorefractive incoherent-to-coherent optical conversion process is analyzed in terms of a simple model that relates the diffracted intensity to the space-variant effective modulation ratio.

Physical Characterization Of The Photorefractive Incoherent-To-Coherent Optical Converter

Photorefractive materials have been extensively used in
recent years as real-time recording media for optical holography.(^1,2) One prospective application of real-time holography is in the area of optical information processing; for example, the correlation between two mutually incoherent images has recently been demonstrated in real time in a four-wave mixing
geometry. (^3) Often, however, the information to be processed exists only in incoherent form. High performance spatial light modulators(^4) are thus necessary in many optical information processing systems to convert incoherent images to coherent replicas for subsequent processing. We report in this Communication the successful demonstration of real-time incoherent-to-coherent images transduction through the use of holographic recording in photorefractive crystals. Several possible configurations and experimental results are presented.

Photorefractive Incoherent-to-Coherent Optical Converter,

Reference EPFL-ARTICLE-158570View record in Web of Science Record created on 2010-11-25, modified on 2017-05-10

Abdel-Latif Marrakchi

Papers

Polarization properties of photorefractive diffraction in electrooptic and optically active sillenite crystals (Bragg regime)

Photorefractive incoherent-to-coherent optical converter

Physical Characterization Of The Photorefractive Incoherent-To-Coherent Optical Converter

Photorefractive Incoherent-to-Coherent Optical Converter,

Photorefractive Incoherent-To-Coherent Optical Conversion