Abstract: A multipass chirped pulse amplification system outfitted with a single-grating, simultaneous spatial and temporal focusing (SSTF) compressor platform is provided. Such a system provides the ability to vary the beam aspect ratio of an SSTF beam, and thus the degree of pulse-front tilt at a focus, while maintaining a net zero-dispersion system. The optical system may include a first optical element or set of optical elements that receives and then varies a pulse-front tilt of a light beam, and a second optical element or set of optical elements that focuses the light beam having the varied pulse-front tilt that is output by the first optical element or set of optical elements. The first optical element or set of optical elements includes an optical grating, two dihedrals, and a retroflector roof mirror.

Abstract: A multipass chirped pulse amplification system outfitted with a single-grating, simultaneous spatial and temporal focusing (SSTF) compressor platform is provided. Such an system provides the ability to vary the beam aspect ratio of an SSTF beam, and thus the degree of pulse-front tilt at a focus, while maintaining a net zero-dispersion system. The optical system may include a first optical element or set of optical elements that receives and then varies a pulse-front tilt of a light beam, and a second optical element or set of optical elements that focuses the light beam having the varied pulse-front tilt that is output by the first optical element or set of optical elements. The first optical element or set of optical elements includes an optical grating, two dihedrals, and a retroflector roof mirror.

Abstract: A two-photon fluorescence microscope employs two laser beams having pulses of respective wavelengths .lambda..sub.2 and .lambda..sub.3, which cause two-photon emission of a fluorophore when the pulses are spatially and temporally overlapping. The pulses of the two beams of wavelengths .lambda..sub.2 and .lambda..sub.3 are combined at some crossing angle .theta. within the specimen, causing two-photon absorption within a line-shaped region during each instant of overlap. As the pulses pass through each other, the overlapping line-shaped region moves such that a slice of the fluorophore-containing specimen is excited by two-photon absorption during the overlap period. Lateral scanning is effected without moving parts by adjusting the relative delay of the pulses in the two beams. When the crossing angle .theta. is set to 0, i.e.