RESUMEN
A background-free, fringe-free form of frequency-resolved optical gating using the third-harmonic signal generated from a glass coverslip is used to characterize 100 fs pulses at the focus of a 0.65 NA objective.
Asunto(s)
Aumento de la Imagen/instrumentación , Rayos Láser , Microscopía de Fluorescencia por Excitación Multifotónica/instrumentación , Óptica y Fotónica/instrumentación , Diseño de Equipo , Análisis de Falla de Equipo , Aumento de la Imagen/métodos , Microscopía de Fluorescencia por Excitación Multifotónica/métodos , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
We demonstrate a significant extension of the high-order harmonic cutoff by using a fully-ionized capillary discharge plasma as the generation medium. The preionized plasma dramatically reduces ionization-induced defocusing and energy loss of the driving laser due to ionization. This allows for significantly higher photon energies, up to 150 eV, to be generated from xenon ions, compared with the 70 eV observed previously. We also demonstrate enhancement of the harmonic flux of nearly 2 orders of magnitude at photon energies around 90 eV when the capillary discharge is used to ionize xenon, compared with harmonic generation in a hollow waveguide. The use of a plasma as a medium for high-order harmonic generation shows great promise for extending efficient harmonic generation to much shorter wavelengths using ions.
RESUMEN
Micro-optic technology is used in a terawatt multipass Ti:sapphire amplifier to convert high-multimode, 532-nm radiation from an unstable resonator Nd:YAG laser into a TEM00 amplified output without sacrificing the amplifier-to-pump energy conversion efficiency. Experimental measurements and Fourier analysis of the spatial mode show a 3.8-fold increase in the peak irradiance and an order-of-magnitude improvement in the spatial contrast.