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Yeshaiahu Fainman

Publications and source records attributed to Yeshaiahu Fainman.

4 recordsLinked to original sources
PubMed2003

Folded shift multiplexing.

Shift multiplexing is a holographic recording method that uses a spherical reference wave. We extend the principle to a thin slab of holographic material that acts as a waveguide. Total internal reflection folds the reference spherical beam in one dimension. We demonstrate that the shift selectivity with the folded spherical beam is independent of the slab thickness but depends instead on the numerical aperture of the coupled spherical wave. A shift selectivity of 0.5 microm has been achieved with a 1-mm-thick LiNbO3 crystal and 50 high-definition data pages are recorded with this method.

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PubMed2002

Single-shot generation of a sonogram by time gating of a spectrally decomposed ultrashort laser pulse.

An experimental technique for single-shot generation of the sonogram of an ultrashort laser pulse is demonstrated. The method is based on the time gating of a spectrally decomposed test signal, transferring its spectral phase into a spatial phase, and the spatial filtering of the signal to produce a sonogram. The technique is evaluated experimentally, producing sonograms for linearly and nonlinearly chirped femtosecond laser pulses. The single-shot technique permits reconstruction of ultrashort pulse complex amplitude profiles and is useful for showing the signal in real time.

Journal Article↗
PubMed2002

Analysis of enhanced second-harmonic generation in periodic nanostructures using modified rigorous coupled-wave analysis in the undepleted-pump approximation.

We present an extension of the rigorous coupled-wave analysis technique to analyze second-harmonic generation (SHG) in periodic optical nanostructures in the undepleted-pump approximation. We apply this method to analyze SHG in two example nanostructures for which we predict enhanced nonlinearity due to transverse near-field localization of the fundamental optical field in the nonlinear material. First, we examine a periodic nanostructure that yields up to twice the transmitted SHG intensity output compared with the bulk nonlinear material but only for small nanostructure depths because of mismatch of the fundamental and second-harmonic mode phase velocities. Second, we develop and analyze a modified nanostructure and find that this nanostructure concurrently achieves transverse localization and phase matching for SHG. In principle, this permits an arbitrary coherent interaction length, and for several specific nanostructure depths we predict a transmitted SHG intensity output more than two orders of magnitude greater than that of the bulk material.

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