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Mode-selective excitation of an infrared-inactive phonon mode in diamond using mid-infrared free electron laser

MetadataDetails
Publication Date2021-08-26
JournalJapanese Journal of Applied Physics
AuthorsRei Akasegawa, Heishun Zen, Kan Hachiya, Kyohei Yoshida, T. Goto
InstitutionsKyoto University, Kumamoto Industrial Research Institute
Citations4

Abstract The direct demonstration was achieved for the selective excitation of the infrared-inactive T 2g mode (1332 cm āˆ’1 ) in the single crystal diamond by two-photon excitation using a mid-infrared free electron laser (MIR-FEL) as pump light. Anti-Stokes Raman scattering light at around āˆ’1339 cm āˆ’1 was observed with cooling at 5 K only when MIR-FEL whose wavenumber was that of one-half of the T 2g mode, 666 cm āˆ’1 , was irradiated. Update of the probe system, i.e. the introduction of the image intensified CCD, made it possible to probe the scattering signal with a lower laser power density compared to our previous study, and it relieved the surface damage on the sample accompanied by laser irradiations which induced a red-shift and a band broadening of the mode in the previous study.