June 25, 2018
Tokyo Institute of Technology
Keio University
Highlights
Controlling the quantum state of optical phonons in diamond using ultrashort light pulses
Developing a theoretical model for the coherent control of coherent optical phonons and reproducing experimental results
Potential application for quantum memory operating at terahertz frequencies using optical phonon states
Summary
A research group led by Associate Professor Kazutaka Nakamura of the Laboratory for Materials and Structures, Institute of Innovative Research at the Tokyo Institute of Technology, in collaboration with Project Associate Professor Yutaka Shikano of the Graduate School of Science and Technology at Keio University and Technical Staff Member Yasuaki Okano of the Institute for Molecular Science, National Institutes of Natural Sciences, has successfully controlled the quantum state of coherent optical phonons in diamond, where atoms collectively vibrate at a frequency of 40 terahertz (THz, or 40 trillion Hz), generated by ultrashort light pulses, and has developed a theoretical model for this phenomenon.
The researchers performed real-time measurements of the change in transmittance caused by diamond coherent phonons vibrating with a 25 fs period, which were generated by near-infrared light pulses with a duration of less than 10 femtoseconds. Furthermore, by using a pair of pulses with high-precision timing control for excitation, they successfully controlled the quantum state of the diamond's coherent optical phonons. They also developed a theoretical model for the coherent control of these phonons by calculating the optical response process in a system composed of vibrational and electronic energy levels, which successfully reproduced the experimental results.
In recent years, research has been conducted on the application of optical phonons in diamond for quantum memory that can operate at room temperature, as their high frequency makes them less susceptible to thermal effects. This study clarifies the operating principle and is expected to enable high-precision control of quantum states.
The research findings will be published in the online edition of the international scientific journal "Scientific Reports" on June 25 (UK time).
For the full press release, please see below.