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تسجيل مستخدم جديدCryogenic Tests of Volume-Phase Holographic Gratings: I. Results at 200 K
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We present results from cryogenic tests of a Volume-Phase Holographic (VPH) grating at 200 K measured at near-infrared wavelengths. The aims of these tests were to see whether the diffraction efficiency and angular dispersion of a VPH grating are significantly different at a low temperature from those at a room temperature, and to see how many cooling and heating cycles the grating can withstand. We have completed 5 cycles between room temperature and 200 K, and find that the performance is nearly independent of temperature, at least over the temperature range which we are investigating. In future, we will not only try more cycles between these temperatures but also perform measurements at a much lower temperature (e.g., 80 K).
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We present results from cryogenic tests of Volume-Phase Holographic(VPH) gratings at 100 K. The aims of these tests are to see whether the diffraction efficiency as a function of wavelength is significantly different at a low temperature from that at
room temperature and to see how the performance of a VPH grating is affected by a number of thermal cycles. We have completed 10 cycles between room temperature and 100 $K$, and find no clear evidence that the diffraction efficiency changes with temperature or with successive thermal cycle.
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The Visible Integral-field Replicable Unit Spectrograph (VIRUS) is a baseline array of 150 copies of a simple, fiber-fed integral field spectrograph that will be deployed on the Hobby-Eberly Telescope (HET). VIRUS is the first optical astronomical in
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We describe a dispersive unit consisting of cascaded volume-phase holographic gratings for spectroscopic applications. Each of the gratings provides high diffractive efficiency in a relatively narrow wavelength range and transmits the rest of the rad
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