A large extinction ratio optical shutter has been demonstrated using electrowetting liquids. The device is based on switching between a liquid-liquid interface curvature that produces total internal reflection and one that does not. The interface radius of curvature can be tuned continuously from 9 mm at 0 V to -45 mm at 26 V. Extinction ratios from 55.8 to 66.5 dB were measured. The device shows promise for ultracold chip-scale atomic clocks.

We differentiate the effect of strain induced by lattice-mismatched growth from strain induced by mechanical deformation on cubic nonradiative Auger recombination in narrow-gap GaInAsSb/GaSb quantum well (QW) heterostructures. The typical reduction in the Auger coefficient observed with lattice-mismatched growth appears to be due to the concomitant compositional change rather than the addition of strain, with implications for mid-IR semiconductor laser design. We induced a range of internal compressive strain in five samples from −0.90% to −2.07% by varying the composition during the growth and mechanically induced a similar range of internal strain in analogous quantum well membrane samples. We performed time-resolved photoluminescence and differential reflectivity measurements to extract the carrier recombination dynamics, taken at 300 K with carrier densities from 2.7×1018 cm−3 to 1.4×1019 cm−3. We observed no change with strain in the cubic Auger coefficient of samples that were strained mechanically, but we did observe a trend with strain in samples that were strained by the QW alloy composition. Measured Auger coefficients ranged from 3.0×10−29 cm6 s−1 to 3.0×10−28 cm6 s−1.

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We measure effect of strain on Auger recombination from compositional and applied biaxial stress using time-resolved photoluminescence and pump-probe spectroscopy. Results suggest that straining by composition, but not external stress, can tune the Auger coefficient.

An intracavity Martinez compressor is incorporated into a fiber laser as a dispersion compensator and spectral filter. The Martinez compressor provides tunable dispersion from normal to anomalous. Inserting a mechanically adjustable slit into the compressor enables tunable spectral filtering independent of dispersion compensation. Mode-locking is achieved with laser bandwidths from 1.8 to 49.0 nm and compressor dispersions from +0.008 to -0.072  ps². The laser generates stable pulses with 0.9 nJ pulse energy, a fundamental repetition rate of 77.5 MHz, and dechirped FWHM pulse widths as short as 82 fs.