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Armstrong, Robert L.

Publications and source records attributed to Armstrong, Robert L..

Optical devices and methods employing nanoparticles, microcavities, and semicontinuous metal films

An optical sensing enhancing material (and corresponding method of making) comprising: a medium, the medium comprising a plurality of aggregated nanoparticles comprising fractals; and a microcavity, wherein the medium is located in a vicinity of the microcavity. Also an optical sensor and sensing method comprising: providing a doped medium, the medium comprising a plurality of aggregated nanoparticles comprising fractals, with the material; locating the doped medium in the vicinity of a microcavity; exciting the doped medium with a light source; and detecting light reflected from the doped medium. Also an optical sensing enhancing material comprising a medium, the medium comprising a semicontinuous metal film of randomly distributed metal particles and their clusters at approximately their percolation threshold. The medium preferably additionally comprises a microcavity/microresonator. Also devices and methods employing such material.

Armstrong, Robert L.↗

Stimulated Raman-scattering threshold behavior of binary mixture micrometer-sized droplets

Stimulated Raman scattering (SRS) from binary liquid mixture micrometer-sized droplets irradiated by nanosecond laser pulses exhibits previously unreported features. SRS emission at wavelength shifts corresponding to combination frequencies of the individual component Stokes shifts are observed in droplets but not in bulk mixtures. Furthermore, droplet SRS thresholds are determined by component refractive indices and concentrations, in contrast to bulk thresholds, for which self-focusing likely plays a dominant role.

Biswas, Abhijit↗