We report designs and results of the dielectric laser reflectors to enhance the damage resistance. Tested samples were titania/silica multilayers and damage testing was done using 1.5 ns pulses at 1.06μm. Damage threshold has been increased by using non-quarter-wave (NQW) design reducing the electric field strength at the titania/silica interface. Another improvement was done by addition of a half wave silica overcoat. The results were applied to the turning mirrors in the GXII target irradiation.
The detection of specified target patterns in a noise image is described that was performed by optical matched filtering technique using a coherent optical system, in which a thermoplastic optical recording device was used for recording the filter. The noise image in which the target patterns were embedded was of perfectly random nature. And it is shown that the thermoplastic optical recording device has characteristics appropriate for recording holographic matched filters and effectively detects the targets in noise images. In the present experiments, the signal-to-noise ratio of 10 in the output image was obtained from the input noise image in which the targets were almost embedded, i. e. the signal-to-noise ratio of 1.
An electron-beam pumped high power argon excimer laser was constructed as a coherent light source for the laser induced fluorescence spectroscopy to measure the concentration of atomic carbon in a fusion-oriented plasma. The laser radiation at 126 nm has been obtained by pumping a commercially purified Ar gas at a pressure of 31 kg/cm2 in a coaxial diode using electron currents of 20∼30 KA and voltages of over 400 KV. The line width of the laser radiation was measured to be 2.5 nm in FWHM and the output laser energy reached to a value of 4.3 mJ, which was 6 times higher than the maximum laser energy reported previously.