1. Development of time-resolved STM and its applications.

We have been carrying out research on a new microscopy technology, optical pump-probe scanning tunneling microscopy (OPP-STM) that enables (1) spectroscopy with femtosecond time resolution (optical pulse width) while (2) confirming the local structure and electronic state of a target with the atomic-level spatial resolution of STM. Figures 1 and 2 show two examples of obtained results for visualizing ultrafast dynamics of carriers (electrons/holes) and spins in nanoscale structures. In this study, we will develop new microscopy technology that enables probing with the spatial resolution of STM with subcycle time resolution. This research is expected to lead to the development of a new scientific field.

In this study, we will realize a measurement method for clarifying the dynamics of subcycles with the resolution of STM. This will be achieved by introducing advanced quantum optics technology, such as the carrier envelope phase (CEP) technique, to directly control the phases of the electric field in pulses. The target local structure is selectively excited while monitoring the surrounding environment by STM because the electric field immediately below the STM probe is amplified about 10⁶-fold. Therefore, a mechanism that enables the measurement of the dynamics of the local structure with subcycle time resolution while controlling the properties in the excited electric field can be realized through the use of the CEP control technique with monocycle pulses.

In general, ultrafast spectroscopy, the relaxation process after excitation is observed. In contrast, with our method, measurement with subcycle time resolution is carried out while controlling the properties of the target. Using the results obtained, molecular functions, which can be the basis for novel function, can be optimally obtained and are expected to lead to a wide range of applications. The targets of measurement include not only molecules but also carriers in semiconductor devices and the dynamics of phase transitions. Thus, the development of a new academic field is expected.

2．Quantum control by coherent phonon

Irradiating solids with femtosecond laser pulses, one can excite coherent lattice vibrations, called as coherent phonons. By precisely control the amplitude, the initial phase, and the frequency of the coherent phonons, we aim to realize quantum control of complexes of carbon nanotubes and proteins, controlling structural phase transitions in topological insulators, and application of these fundamental physics to exploiting quantum elements.

3．Development of cell imaging technology

We aim to develop new molecular imaging method using nonlinear Raman spectroscopy.

4．Protein solution technology

We aim to develop technology to various solution states of protein.

5．Quantum-Biological control

By controlling the dynamics of cells and each element at the molecular level by external field, we, for example, aim to clarify the mechanism of canceration and to develop new therapies.