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The optical properties of PbSe quantum dots (QDs) in AB9093 epoxy nanocomposite are examined with respect to temperature over a range of 0°C–80°C, a useful working range for many QD-based sensors and devices, and results are compared to QDs in toluene solution. A complete characterization of QD optical properties is provided as a function of temperature, including the absorption spectrum, first excitonic (1-s) absorption peak intensity and wavelength, fluorescence intensity, and peak wavelength. QD optical properties in toluene were found to be more sensitive to temperature as compared to those in AB9093. Interestingly, 1-s and fluorescence peak wavelength variation with temperature are reversed in AB9093 as compared to those in toluene solution. Results for the fluorescence properties of Lumogen F Red 305 dye in toluene are presented for comparison. The dye was found to have similar sensitivity to temperature to that of the QDs in terms of fluorescence peak wavelength shift, but the fluorescence peak intensity was far less variant. These results can be used to build a temperature sensor or as a guide to building other types of QD-based devices to be more robust against changes in ambient temperature.

We develop a general vectorial model of two-frequency nonlinear pulse propagation in multi-mode optical waveguides, including mixing effects between modes and polarizations across both frequencies, resulting in nontrivial new terms in the amplitude propagation equations. We present rules for calculating these terms from simple diagrammatic representations of physical processes. The corresponding coefficients are computed numerically for a simple step index fiber, demonstrating that even in the simplest case of a cylindrical fiber, these coefficients are significant in magnitude. These additional terms predict a higher gain for third harmonic generation than equivalent models without mode and polarization mixing effects, and also predict power exchange between orthogonal polarizations and non-phase-matched modes in the waveguide. Refereed/Peer-reviewed