39 research outputs found
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Optical switching and contrast enhancement in intense laser systems by cascaded optical parametric amplification
Optical parametric chirped-pulse amplification (OPCPA) can be used to improve the prepulse contrast in chirped-pulse amplification systems by amplifying the main pulse with a total saturated OPCPA gain, while not affecting the preceding prepulses of the seed oscillator mode-locked pulse train. We show that a simple modification of a multistage OPCPA system into a cascaded optical parametric amplifier (COPA) results in an optical switch and extreme contrast enhancement which can completely eliminate the preceding and trailing oscillator pulses. Instrument-limited measurement of prepulse contrast ratio of 1.4 x 10{sup 11} is demonstrated from COPA at a 30-mJ level
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Extreme prepulse contrast utilizing cascaded-optical parametric amplification
It has been shown recently that an optical parametric chirped-pulse amplifier can be easily reconfigured into a cascaded-optical parametric amplifier (COPA), enabling complete prepulse removal and optical switching with a window defined by the pump pulse duration. We have demonstrated instrument-limited measurement of the COPA prepulse contrast >1.4 x 10{sup 11} using 30-mJ pulses. The COPA technique is applicable to all energy ranges and pulse durations. A convenient millijoule-scale implementation of this technique is presented using a single, large-aspect-ratio quasi-phase-matched nonlinear crystal
Reconstruction 3D, sur un microscope standard, d'un échantillon biologique par tomographie diffractive en illumination spatialement incohérente
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Beam-focus shaping by use of programmable phase-only filters: application to an ultralong focal line
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Quantitative birefringence imaging of biological samples using quadri-wave interferometry
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Tissue Tomographic Phase Image Contrast Improvement with Adaptive Optics
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Microscopie de phase quantitative par analyse de front d'onde
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