权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Coherent control of one-photon forbidden transitions in semiconductors

半导体中单光子禁戒跃迁的相干控制

基本信息

批准号：
10440088
负责人：
MINAMI Fujio
金额：
$ 8.45万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10440088/
关键词：
coherent control femtosecond optical pulse 2p exciton quantum beat phase relaxation ZnSe thin film resonant hyper Rayleigh scattering フェムト秒光パルス 2光子散乱現象位相間和

项目摘要

The coherent control technique, where a relative phase of two femtosecond optical pulses is controlled precisely, gives us a new method controlling freely optical transitions in the semiconductors. Combining this coherent control technique with the resonant hyper-Rayleigh scattering, we developed a new spectroscopic method to manipulate the wavefunctions of one-photon forbidden states in semiconductors. This method was applied to the coherent control of one-photon forbidden 2p exciton states in ZnSe thin film on GaAs substrate. As a result, it was found that the 2p excitonic polarization can be manipulated freely by controlling the relative phase between incidence two pulses, and that the phase relaxation time of the 2p exciton state is -2ps. In addition, the quantum beat signal was superimposed to the obtained signal. This means that the 2p exciton state is split to a heavy hole and light hole states due to the strain caused by the lattice mismatch between ZnSe and GaAs. It is found from the period of the quantum beat that the energy separation between the heavy hole and light hole 2p extions is about 2meV.Next, we investigated the symmetry of the 2p exciton state in ZnSe by changing the relative direction of the polarizations of two pulses. It is found that the heavy hole and light hole 2p excitons belong to different symmetry. The spectrum information shows that the wavefunction of the heavy hole 2p exciton is s-like. Whereas, as for the light hole 2p exciton, the wavefunction has d-like symmetry. Moreover, the selection rule of resonant hyper-Rayleigh scattering process involving the 2p exciton states is found to be different from that of the SHG process.

精确控制两个飞秒光脉冲的相对相位的相干控制技术为我们提供了一种自由控制半导体中光学跃迁的新方法。将这种相干控制技术与共振超瑞利散射相结合，我们开发了一种新的光谱方法来操纵半导体中单光子禁态的波函数。该方法应用于GaAs衬底上ZnSe薄膜中单光子禁戒2p激子态的相干控制。结果发现，通过控制入射两个脉冲之间的相对相位，可以自由地操纵2p激子极化，并且2p激子态的相位弛豫时间为-2ps。此外，将量子拍频信号叠加到所获得的信号上。这意味着由于ZnSe和GaAs之间的晶格失配引起的应变，2p激子态分裂为重空穴和轻空穴态。从量子拍周期发现，重空穴和轻空穴2p激发之间的能量间隔约为2meV。接下来，我们通过改变两个脉冲偏振的相对方向来研究ZnSe中2p激子态的对称性。发现重空穴和轻空穴2p激子属于不同的对称性。光谱信息显示重空穴2p激子的波函数是类s的。而对于光孔2p激子，波函数具有类d对称性。此外，发现涉及2p激子态的共振超瑞利散射过程的选择规则与SHG过程的选择规则不同。