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Ishiguro, Masazumi; Aratono, Yasuyuki
Review of Scientific Instruments, 76(2), p.026106_1 - 026106_4, 2005/02
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)Simple and widely applicable microwave spectroscopy system for the low temperature condensed media has been developed. We applied the technique of opto-thermal detection with superconducting thin-film sensor (STS) for the detection of very weak absorption signal of molecules trapped in quantum solid and liquid such as solid para-hydrogen (
-H
) and bulk liquid helium. For the test of the system, the microwave transition of ortho-hydrogen (
-H) pair in solid -H was observed. The S/N ratio of the observed spectrum of the G
transition at 1.4 K was approximately 8. Ultra high sensitivity of STS makes it possible not only to obtain sufficient sensitivity but also to make the apparatus very simple especially around the sample cell.
Gordon, E. B.*; Kumada, Takayuki; Ishiguro, Masazumi; Aratono, Yasuyuki
Journal of Experimental and Theoretical Physics, 99(4), p.776 - 783, 2004/10
The solid Deuterium clusters for the first time isolated in a matrix of solid Helium have been investigated at T = 1.3K and P = 3 MPa by CARS (Coherent anti-Stokes Raman spectroscopy) technique. The Q1(J=0) and Q1(J=1) lines intensity, shape and positions have been studied as the functions of ortho- para content in the solid, as well as of clusters size. The strong effect of Raman scattering cross section sensitivity to the molecular environment nuclear spin state has been found in CARS; the ratio of probabilities for the scattering by para (J=1) and ortho (J=0) deuterium being equal to 1 in a gas is as high as 10,000 in nearly pure o-D2, whereas it is about 50 in spontaneous Raman scattering. This effect has been shown to give rise starting from cluster size corresponding to the phonon band onset.
