[11a-N106-1~10] 3.8 Optical measurement, instrumentation, and sensor

[11a-N106-7] Development of a Brillouin spectrometer with variable FSR

〇Hidekazu Ishitobi^1,2,3, Atsushi Sawa², Yasushi Inouye^1,2,3 (1.FBS, Osaka Univ., 2.Dept. of Applied Physics, Osaka Univ., 3.PhotoBIO-OIL, AIST-Osaka Univ.)

Keywords:Brillouin scattering, VIPA, FSR

Brillouin scattering spectroscopy has been studied as a method for non-invasively measuring the viscoelasticity of a matter by light. In this study, we newly designed an air gap VIPA that can control FSR by changing distance between two independent Solid etalons arranged in parallel, and evaluated their spectral characteristics and stability. As a result, we succeeded in changing the FSR from 9.4 to 55.5 GHz. We also succeeded in obtaining the same S/N ratio as that by Solid VIPA. Furthermore, the Brillouin scattered light could be measured stably for at least 3 hours.