INTRODUCTION OF LABORATORY

A photoinduced phase transition is a phenomenon, in which an electronic and crystal structures are changed by a photoirradiation. In our laboratory, we are exploring various photoinduced phase transitions and clarifying their mechanisms by using an ultra-short laser pulses with a temporal width of 100~7 fs (fs = 10−15 s). For example, a Mott insulator of copper oxides can be converted to a metal by a laser-pulse irradiation via the melting of the electron order (Fig. 1). In some kind of molecular materials, a Van-der-Waals-type neutral crystal can be converted to an ionic one by a laser-pulse irradiation. In this transition, the rapid changes of molecular valences are accompanied by changes of molecular structures and positions, which can be detected as oscillatory signals on the optical re-ectivity change (Fig. 2). When a ferroelectric or ferromagnetic crystal is irradiated with a visible laser pulse, a terahertz electromagnetic wave is emitted via the modulation of the polarization or magnetization. By measuring its waveform at various positions in a crystal, we can visualize the ferroelectric or ferromagnetic domains (Fig. 3).

HIROSHI OKAMOTO & NORIAKI KIDA LAB. research

 

光励起により金属化する銅酸化物

HIROSHI OKAMOTO & NORIAKI KIDA LAB. research

 

光励起による分子性結晶(TTF-CA)の中性-イオン性転移のダイナミクス

HIROSHI OKAMOTO & NORIAKI KIDA LAB. research

 

テラヘルツ電磁波測定による有機強誘電体の分極ドメインの可視化

Message

SET HIGH GOALS AND DO YOUR RESEARCHES TO ACHIEVE YOUR OWN DREAM.

Our research is to clarify and control electronic properties of condensed matter by using various kinds of laser lights with different frequencies and temporal widths. By utlizing unique features of correlated electron and/or low dimensional electron systems in transition metal compounds and organic molecular materials, we expect to achieve the final goal of making next-generation optical devices, which show the higher peformance than those based upon convential semiconductors. In just the past thirty years, the optical technology has been extensively improved. Thirty years ago, we did not imagine that we could detect directly dynamics of electrons, spins, atoms and molecules in solids, but now we can do that by using ultrashort laser pulses. We hope that students set high goals and make researches to achieve their dreams. In our laboratoy, a lot of students have thus far made fascinating discoveries. We believe that all the new students will be able to experience their own discoveries, each of which is the world’s first one.

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