Coherent, Inc.
SPECTRALLY BROADENING ULTRASHORT-PULSE COMPRESSOR

Abstract:

An ultrashort-pulse compressor includes (a) one or more bulk-optics intersecting a propagation path of an ultrashort-pulsed laser beam multiple times to spectrally broaden a pulse of the laser beam during each of multiple passes through the bulk-optic(s), (b) one or more dispersive optics for compressing a duration of the pulse after each of the multiple passes, and (c) a plurality of focusing elements for focusing the laser beam between the multiple passes. Propagation distances between the bulk-optic(s) and the focusing elements are detuned from imaging such that a spot size of the laser beam, at the bulk-optic(s), is greater at each successive one of the multiple passes. As the laser beam propagates through this compressor, each laser pulse is alternatingly spectral broadened and temporally compressed. The increasing spot size of the laser, for each pass, helps prevent optical damage, run-away self-focusing, and other undesirable outcomes.