A. M. Malvezzi

TL;DR: In this article, the femtosecond pump-and-probe spectroscopy was used to detect photo-induced differential reflection in the picosecond time domain and the measured period increases linearly with size over a wide range and extracted sound velocities are consistent with those of bulk.

TL;DR: Metis as mentioned in this paper is the first solar coronagraph designed for a space mission and is capable of performing simultaneous imaging of the off-limb solar corona in both visible and UV light.

Abstract: Second-harmonic generation (SHG) measurements in reflection on a ${\mathrm{G}\mathrm{a}\mathrm{A}\mathrm{s}/\mathrm{A}\mathrm{l}}_{0.25}{\mathrm{Ga}}_{0.75}\mathrm{As}$ photonic crystal waveguide show a resonant enhancement when the pump beam is frequency and momentum matched with the photonic modes in the slab. The enhanced SH signal is observed in the form of resonant peaks, unlike in linear reflectance spectra. The observations are in very good agreement with a full 3D calculation of the anisotropic mode dispersion in the photonic crystal slab. The present results open the way towards realizing the extraordinary enhancement of SHG which was recently predicted [A. R. Cowan and J. F. Young, Phys. Rev. B $65,$ 085106 (2002)], and also demonstrate the potential of SHG as a nonlinear spectroscopic tool for optical studies of photonic crystals.

TL;DR: In this article, the authors observed visible second-harmonic and ultraviolet thirdharmonic fields generated in reflection from the surface of a two-dimensional triangular GaN/sapphire photonic crystal when the pump radiation resonates with a photonic mode.

TL;DR: In this article, second-harmonic generation (SHG) measurements in reflection on nativeoxide-covered porous silicon samples and on (1 − 0 − 0) p-type doped crystalline silicon wafers have been performed.