Second harmonic generation in a two dimensional nonlinear quasi-crystal is demonstrated for the first time. Temperature and wavelength tuning of the crystal reveal the uniformity of the pattern while angle tuning reveals the dense nature of the crystal's Fourier spectrum. These results compare well with theoretical predictions showing the excellent uniformity of the crystal and suggest that more complicated "nonlinear holograms" should be possible.
Lineshapes of degenerate four-wave mixing signals induced by both monochromatic and nonmonochromatic lasers are compared with predictions of the non-perturbative model of Bratfalean, Lloyd and Ewart (BLE model) for the interaction of pump and probe beams of arbitrary intensity. Spectral lineshapes of isolated lines in DFWM spectra of OH in a methane-oxygen flame were recorded using a novel single-mode tunable laser as a function of laser power. Power broadening of the lineshapes was found, in this case of an essentially monochromatic laser, to be well described by the BLE model. DFWM lineshapes of more complex molecular spectra were recorded in C 2 in an oxy-acetylene flame using a standard, non-monochromatic, dye laser. Lineshapes of closely spaced molecular resonances were found to be appreciably affected by saturation or power broadening effects. These effects were reasonably well approximated by the non-perturbative BLE model when adapted to take account of the finite laser bandwidth. In contrast, the experimental lineshapes of the C 2 spectra for saturating fields could not be modeled using the standard perturbative model of Abrams and Lind
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.