Derivation and measurement of the reversible temporal lengthening of femtosecond optical pulses for the case of a four-prism sequence.

An expression is derived for the reversible lengthening of optical pulse durations from the order of 50 fsec to the order of 500 fsec by a four-prism sequence and focusing elements. This temporal lengthening is caused by spatial dispersion of the different frequency components transverse to the direction of propagation at the symmetry plane of the prism sequence. Experimental measurements of the pulse lengthening agree well with calculated values.

Amplification of femtosecond optical pulses using a double confocal resonator.

We experimentally examine a class of multipass amplifiers based on an open double confocal resonator. A preamplifier provides a gain of 800. An intermediate-stage amplifier produces pulse energies of 2 microJ for only 1.

Aerosol particle analyzer.

A new multiangle light scattering instrument is described for the classification of single aerosol particles in a flowing gas stream. Simultaneous measurement at sixteen scattering angles over the surface of a spherical chamber permits determination of a variety of optical observables useful for the subsequent characterization of each measured particle. Particles of 0.