Evaluation of polymer based third order nonlinear integrated optics devices

Nonlinear polymers are promising materials for high speed active integrated optics devices. In this paper we evaluate the perspectives polymer based nonlinear optical devices can offer. Special attention is directed to the materials aspects. In our experimental work we applied mainly Akzo Nobel DANS side-chain polymer that exhibits large second and third order coefficients. This material has been characterized by third harmonic generation, z-scan and pump-probe measurements. In addition, various waveguiding structures have been used to measure the nonlinear absorption (two photon absorption) on a ps time-scale. Finally an integrated optics Mach-Zehnder interferometer has been realized and evaluated. It is shown that the DANS side-chain polymer has many of the desired properties: the material is easily processable in high-quality optical waveguiding structures, has low linear absorption and its nonlinearity has a pure electronic origin. More materials research has to be done to arrive at materials with higher nonlinear coefficients to allow switching at moderate light intensity (< 1 W peak power) and also with lower nonlinear absorption coefficients

Measured optical absorption coefficients for uranium plasmas

Absolute emissivities of uranium plasmas in gas driven shock tub

Intracavity Dye-Laser Absorption Spectroscopy (IDLAS) for application to planetary molecules

Time-resolved, quasi-continuous wave, intracavity dye-laser absorption spectroscopy is applied to the investigation of absolute absorption coefficients for vibrational-rotational overtone bands of water at visible wavelengths. Emphasis is placed on critical factors affecting detection sensitivity and data analysis. Typical generation-time dependent absorption spectra are given

Measurement and Modeling of Infrared Nonlinear Absorption Coefficients and Laser-induced Damage Thresholds in Ge and GaSb

Using a simultaneous fitting technique to extract nonlinear absorption coefficients from data at two pulse widths, we measure two-photon and free-carrier absorption coefficients for Ge and GaSb at 2.05 and 2.5 μm for the first time, to our knowledge. Results agreed well with published theory. Single-shot damage thresholds were also measured at 2.5 μm and agreed well with modeled thresholds using experimentally determined parameters including nonlinear absorption coefficients and temperature dependent linear absorption. The damage threshold for a single-layer Al2O3 anti-reflective coating on Ge was 55% or 35% lower than the uncoated threshold for picosecond or nanosecond pulses, respectively

Lidar temperature profiling: Performance simulations of Masons method

Several methods of using lasers to measure atmospheric temperature profiles were described. Mason's suggestion was analyzed here to assess its capabilities for various lidar configurations. Temperatures were inferred from a measure of the Boltzmann distribution of rotational states in one of the vibrational bands of O2. Differential absorption was measured using three tunable, narrowband pulsed lasers. The outputs of two were tuned to wavelengths at the centers of absorption lines at either end of a particular branch in the band. The third wave-length was in a region of no absorption; its lidar return measured only the atmospheric backscatter, and therefore allowed calculations of the absorption coefficients at the other two wavelengths as a function of altitude. From the ratio of the two line absorption coefficients plus a priori knowledge of the line parameters, the temperature-altitude profile were calculated

Sensitivity of p-mode absorption on magnetic region properties and kernel functions

Aims. Magnetohydrodynamic (MHD) sausage tube waves are excited in magnetic flux tubes by p-mode forcing. These tube waves carry energy away from the p-mode cavity which results in a source of absorption. We wish to see the effect of an ensemble of randomly distributed thin magnetic flux tubes on the absorption of p-modes for the model plage region and also study the effect of the spacial weighting function on the theoretically calculated absorption coefficients. Methods. We calculate the absorption coefficients of p modes for a model plage, assumed to consist of an ensemble of many thin magnetic flux tubes with randomly distributed plasma properties. Each magnetic flux tube in the ensemble is modelled as axisymmetric, non-interacting, vertically oriented and untwisted. Results. We find that the magnitude and the form of the absorption coefficient is sensitive to the plasma-beta of the tubes which is consistent with previous work. Both the random distribution used to model the ensemble of flux tubes and the spatial weighting function inherent to the measurement of the absorption affect the absorption. As the width of the weighting function increases, the absorption increases