Joel M. Murray

Measuring refractive index using the focal displacement method

A simple technique is introduced for measuring the refractive index of plane-parallel samples having thickness of the order of a millimeter. The refractive index values are reported for six bulk semiconductors, each index measured at two infrared wavelengths using this method. The values are found to be within a few percent of those in literature for four semiconductors. The other two semiconductors were newly grown ternary alloys (CdMgTe and CdMnTe), for which the refractive index values have not been reported previously at the wavelengths studied here.

Measurement of the nonlinear optical properties of semiconductors using the irradiance scan technique

Irradiance scan measurements of the nonlinear absorption and refraction coefficients of CdTe were performed at room temperature and at 77 K and compared to the values obtained in previous experiments using a different technique.

Comparison of nonlinear absorption and carrier recombination times in GaAs grown by hydride vapor phase epitaxy and Bridgman processes

μA 760 μm thick GaAs crystal was grown using HVPE. Transmission spectrum of this sample showed minimal absorption for light having photon energy below the bandgap energy, indicating the absence of the EL2 defects commonly found in Bridgman grown samples. Irradiance dependent absorption measured at 1.535 μm using 100 ns duration laser pulses showed increased nonlinear absorption in the HVPE grown GaAs compared to Bridgman grown samples. The dominant nonlinear absorption process in both samples was absorption due to free carriers generated by two-photon absorption. The HVPE grown sample showed higher nonlinear absorption due to longer carrier lifetimes.

Measurement of refractive indices of CdSiP 2 at temperatures from 90 to 450 K

Ordinary and extraordinary refractive indices of CdSiP2 were measured and a Sellmeier equation was obtained for the first time to our knowledge over the temperature range 90 to 450 K. The index values were used to calculate the crystal temperature and phase-matching angle dependence of the generated wavelengths in the nonlinear frequency conversion of a range of pump wavelengths. A good match was obtained between the calculated values of the wavelengths and some experimental measurements.

Broadband saturable and reverse saturable absorption in graphene-based nanocomposites

Nonlinear optical studies are carried out on graphene-based polymer composites in the nanosecond and picosecond temporal regime. These graphene-composites demonstrate saturable absorption followed by reverse saturable absorption which depends on graphene content and operation regime.

Temperature and wavelength dependence of the nonlinear optical parameters of InP

Values of the nonlinear absorption and nonlinear refraction coefficients of InP were measured at different temperatures using picosecond and nanosecond durations lasers operating at 1064 nm and 1570 nm.

Experimental and Theoretical Study of the Nonlinear Optical Properties of III-V Ternary Semiconductor Alloy Crystals

Nonlinear optical properties of novel ternary semiconductor crystals were determined at several wavelengths between 1 and 2 micrometers using a wavelength tunable, picosecond duration laser. Measured values were compared to theoretical calculations.