Kentaro Somiya
- Professor, Associate Investigator
I finished my PhD at Univ of Tokyo working on a prototype RSE experiment. One of the goals is to develop a good control scheme for second generation GW detectors. The control method was selected as the control scheme for aLIGO. I was invited to MIT in 2006 and developed a tool to calculate shot-noise-limited control loop noise, which enabled us to compare different control methods proposed at the time. The tool was later combined with Opticle and is being used for many GW detectors. Another goal of my thesis is to examine an optical spring in the detuned RSE interferometer. We did see the first sign of the optical spring effect, which was later more clearly observed at Caltech and MIT.
After postdocs at AEI and Caltech, I moved back to Japan, working for KAGRA. I played a role of a system engineer and contributed to the construction of the telescope. My paper titled “Detector configuration of KAGRA” has been the most cited paper that represents KAGRA. Tokyo Tech (former name of Sci Tokyo) was in charge of two items; input Faraday isolator and output mode cleaner. Both of them were successfully installed in the detector.
Since 2012, I have been working on the intracavity quantum filter technique to improve the sensitivity of GW detector. There are various possible quantum filters, but one promising filter is the OPA in the signal recycling cavity. With the detuning, it enhances the optical spring frequency possibly to a few kHz band. We propose this technique for GEO-HF and other detectors aiming at high frequency GWs. Our proposal to develop such a quantum filter for GW detectors was accepted for a 5.5-year project called ASPIRE. A goal of the project is to explore a 2.5-generation GW telescope like NEMO or KAGRA+ that observes a clear footprint of BNS mergers or other high frequency new physics. ASPIRE is an Australian-Japanese bilateral program and We would like to contribute to the OzGrav.
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