  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).
