Quantum Photo-Science Laboratory

Staff & Contact

Educational Staff	Prof. Hiroyuki Katsuki Assistant Prof. Stemo Garrek
Contact	TEL: +81-743-72-6010
URL	https://qps-lab-naist-en.labby.jp/

Education and Research Activities in the Laboratory

The Quantum Photo-Science Laboratory studies molecules, crystals, nanoparticles, and ultrathin films of both organic and inorganic materials, utilizes various optics-based experimental approaches to clarify material properties from the viewpoint of quantum physics, and aims to create new functional materials that will be used in optical information-communication or environment-conscious devices in the future.

Research Theme

1. Ultrafast dynamics of vibrational polaritons

Vibrational polariton is a mixed quasiparticle of Mid-IR photon and molecular vibrational motion. Recently, it is shown that the formation of vibrational polariton can affect various properties of molecules. We apply ultrafast spectroscopic techniques to reveal the background physics and chemistry of such new phenomena.

2. Coherent control of condensed phase quantum states

Coherent control is a technique to manipulate the quantum wavefunction of target systems by precisely designed laser pulses. We apply this technique to control the coherent phonon motion in various single crystalline systems. Our goal is to trigger a photo-induced phase transition induced by electron-phonon interactions.

3. Photo-physical properties of nanocrystals of organic semiconductors

For the first time, we observed a blueshift in optical spectra as the size of organic nanocrystals decreases. This phenomenon reflects quantum effects in the organic nanocrystals. We aim to elucidate the mechanism of the quantum effects in the organic nanocrystals. We have also worked on full-color OLEDs using the quantum effects in the organic nanocrystals.

Explanatory Pictures of Research Activities

Fig. 1 Experimental setup for ultrafast nonlinear spectroscopy

Fig. 2 band structure of vibrational polaritons

Fig. 3 size-dependent photoluminescence of organic semiconductor nanocrystal and its application

Recent Research Papers and Achievements

Development of spacer-less flow-cell cavity for vibrational polaritons,　Hayata Yamada, Garrek Stemo, Hiroyuki Katsuki, and Hisao Yanagi,　J. Phys. Chem. B 126, 4689-4696 (2022).
Controlling ultrafast wave-packet spreading by Strong-Laser-Induced quantum interference, Hiroyuki Katsuki, Yukiyoshi Ohtsuki, Toru Ajiki, Haruka Goto, and Kenji Ohmori, Phys. Rev. Research 3, 043021 (2021).
Polymorph- and molecular alignment-dependent lasing behaviors of a cyano-substituted thiophene/phenylene co-oligomer,Tomomi Jinjyo, Hitoshi Mizuno, Fumio Sasaki, and Hisao Yanagi, J. Mater. Chem. C 11, 1714-1725 (2023).
Observation of Size-Dependent Optical Properties Based on Surface and Quantum Effects in Nanocrystals of 5,5′-Bis(4-Biphenylyl)-2,2′-Bithiophene, Tomomi Jinjyo, Hitoshi Mizuno, Kazuki Bando, Fumio Sasaki, Hisao Yanagi, Adv. Photonics Res. 3, 2100323 (2022).