The laser-induced incandescence of a particle of unknown size and composition can be detected simultaneously with the light elastically scattered by the particle, providing information on both the size and composition of the particle. The technique relies on vaporization of the particle; detection of the incandescence signal at the time of vaporization allows determination of the boiling point of the particle, which can in turn be related to the composition of the particle. The elastically scattered signal provides information about the size of the particle and confirmation that it was vaporized. The technique is demonstrated by directing particles through a Nd:YAG laser cavity with approximately 10(6) W/cm2 of circulating intensity. Elements such as tungsten, silicon, and graphite, as well as common aerosols such as soot, can be detected and identifed.

The Laser Ranging Interferometer (LRI) instrument on the Gravity Recovery and Climate Experiment (GRACE) Follow-On mission has provided the first laser interferometeric range measurements between remote spacecraft, separated by approximately 220 km. Autonomous controls that lock the laser frequency to a cavity reference and establish the 5 degree of freedom two-way laser link between remote spacecraft succeeded on the first attempt. Active beam pointing based on differential wavefront sensing compensates spacecraft attitude fluctuations. The LRI has operated continuously without breaks in phase tracking for more than 50 days, and has shown biased range measurements similar to the primary ranging instrument based on microwaves, but with much less noise at a level of 1 nm/ √ Hz at Fourier frequencies above 100 mHz.

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Efficient collection of atoms into a vapor-cell laser trap requires a special wall material for the cell that minimizes the interactions between the vapor and the wall. Tests of several different wall coatings and materials are reported, and measurements of adsorption energies, outgassing, and chemical reaction rates between the alkali vapor and the walls are described. It is demonstrated that each of these parameters affects the collection efficiency.