While most properties of material are determined by the characteristics of constituent atoms and molecules, sometimes new and exotic optical and electromagnetic properties may appear in the coherent state, in which many atoms and molecules share a common phase factor.  In our laboratory, we are interested in the quantum mechanical properties of materials, including the microcavity polaritons, coherent phonons, and  organic semiconductor nano-crystals. We utilize lasers to investigate the ultrafast dynamics of such systems, looking for the applications such as polariton-based catalysis for chemical reactions, light emitting devices and photo-switching devices. Please check the links below for detailed explanation.

Introduction for coherent control
Thanks to recent highly developed pulse shaping techniques, we can manipulate various properties of laser pulses, such as the spectrum, temporal envelope, spatial mode, etc. Coherent control is a technique to manipulate the amplitude and phase distribution of target quantum systems utilizing these pulse-shaping techniques. Its application covers variety of systems from isolated molecules to complicated many-body systems. Here we introduce the basics of coherent control with simple systems.
manipulation of coherent phonons
Coherent phonons are phonon motions defined by the well-defined phase of neighboring atoms (molecules) that are excited by ultrashort pulse irradiation. With the application of coherent control described in previous sections, it is also possible to control the amplitude of phonons. We are currently working on the application of this technique to control the bulk properties of the target crystals.
Cavity exciton polaritons and vibrational polaritons
By confining light and matter to a tiny region with the scale of the wavelength of light, new quantum states (polariton states) are formed in which the light and matter are mixed together. In these polariton states, many molecules are known to cooperatively combine through delocalized light and exhibit chemical and physical properties different from those of ordinary molecules. We are pursuing the origin of the novel properties exhibited by the polariton states by femtosecond lasers, and are aiming to manipulate their ultrafast dynamics.