We present the results of an investigation of the nonlinear characteristics of a new class of robust, multimaterial, allsolid chalcogenide nanotapers prepared from high-index-contrast chalcogenide fibers. The fiber is drawn from a preform produced by multimaterial coextrusion and consists of chalcogenide core and cladding (which dictate the optical properties) and a built-in thermally compatible polymer jacket that provides mechanical stability to the fibers and nanotapers. We measure the nonlinear refractive indices both in the bulk chalcogenide glasses using the Z-scan method and directly in the nanotapers from spectral broadening resulting from self-phase modulation using both picosecond and femtosecond pulses. Such robust nanotapers offer many opportunities for dispersion engineering to optimize nonlinear optical fiber applications such as infrared supercontinuum generation. Lowpower femtosecond pulses (∼100 W peak power, corresponding to ∼40 pJ energy per pulse) centered at 1.55 μm wavelength launched into the nanotapers generated a supercontinuum extending over a full spectral octave, 1-2 μm. A computational model that takes into account the relevant linear and nonlinear optical parameters provides simulations that are in good agreement with the supercontinuum measurements.

We report on infrared supercontinuum generation extending over more than one octave of bandwidth, from 850 nm to 2.35 μm, produced in a single spatial mode from a robust, compact, composite chalcogenide glass nanotaper. A picosecond laser at 1.55 μm pumps a high-index-contrast, all-solid nanotaper that strongly confines the field to a 480 nm diameter core, while a thermally compatible built-in polymer jacket lends the nanotaper mechanical stability.

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Abstract. The use of physical vapor deposition is an attractive technique to produce microenergetic samples to study sub-millimeter explosive behavior. Films of the high explosive PETN (pentaerythritol tetranitrate) were deposited through vacuum thermal sublimation. Deposition conditions were varied to understand the effect of substrate cooling capacity and substrate temperature during deposition. PETN films were characterized with surface profilometry and scanning electron microscopy. Detonation velocity versus PETN film thickness was analyzed using a variation of the standard form for analysis of the diameter effect. Results were compared with previous work conducted on PETN films deposited with lower substrate cooling capacity. Seemingly subtle variations in PETN deposition conditions led to differences in detonation behaviors such as critical thickness for detonation, detonation velocity at "infinite" thickness, and the shape of the critical thickness curves.