Detection of quantum coherence in a bulk solid using the interferometric transient reflectivity measurement

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K13377
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Optical engineering, Photon science
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: Nakamura Kazutaka 東京工業大学, 科学技術創成研究院, 准教授 (20302979)
• Co-Investigator(Renkei-kenkyūsha): SHIKANO Yutaka 慶應義塾大学, 理工学部, 特任准教授 (80634691) ; KAYANUMA Yosuke 東京工業大学, 科学技術創成研究院, 特任教授 (80124569)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 量子コヒーレンス / コヒーレントフォノン / フェムト秒パルス / 過渡反射率計測

Outline of Final Research Achievements

We developed a new technique to measure quantum coherence in a bulk solid using a pair of phase-locked femtosecond pulses and a pump-pump-probe type transient reflectivity measurement (interferemetric transient reflectivity measurement). Using this technique, we measured the quantum coherence in electron-phonon coupled states in a semiconductor GaAs crystal and found that the electronic coherence is preserved during approximately 50 fs at 90 K. We also developed the theory for generation mechanism of the coherent phonons by using a simple model with two electronic states and harmonic potentials. We calculated time evolution of the states by solving the time-dependent Schrodinger equation with a density matrix formalism and second-order perturbation.

Free Research Field

光物性