US-Korea Cooperative Research in Nonlinear Laser Spectroscopy of Semiconductor Heterostructures

该奖项将资助俄克拉荷马州立大学激光研究中心的Jin-Joo Song博士与韩国首尔国立大学物理系的Dai-Sik Kim博士进行为期24个月的半导体异质结构非线性激光光谱的合作研究。在这项研究中，合作者计划研究最近在宽禁带材料中发现的强飞秒非线性，如ZnSe、ZnCdSe/ZnSe量子阱或GaN，这些材料在技术上越来越重要。利用飞秒钛蓝宝石激光器的二次谐波，在激子共振附近进行飞秒波混合实验。这些实验将在不同条件和不同基质下生长的各种样品上进行不同强度、极化和温度的实验。为了研究极性和带隙对飞秒非线性的影响，将对GaN或InGaN的飞秒非线性进行研究。通过在金刚石砧腔中进行四波混频实验，分离了带隙变化对飞秒非线性的影响。合作者希望通过这些和其他新颖的实验获得宽禁带材料飞秒非线性的连贯图像。通过他们的研究，合作者将扩展所选半导体材料类别的知识前沿，其中一些可能具有有用的电子应用。合作者在他们所提议的项目领域具有相当丰富的互补研究经验。该项目与美韩合作科学项目的目标相关，该项目旨在通过科学信息、思想、技能和技术的交流以及在互利问题上的合作，提高美韩科学家和工程师之间的合作水平。韩国部分参与该项目得到了韩国科学工程财团（KOSEF）的支持。＊＊＊

9513197 Song This award provides funds to permit Dr. Jin-Joo Song, Center for Laser Research, Oklahoma State University, to pursue with Dr. Dai-Sik Kim, Department of Physics, Seoul National University, Korea, for 24 months, a program of cooperative research on nonlinear laser spectroscopy of semiconductor heterostructures. In this study, the collaborators plan to investigate recently found strong femtosecond nonlinearities in wide band gap materials such as ZnSe, ZnCdSe/ZnSe quantum wells, or GaN, that are of increasing technological importance. Femtosecond wave mixing experiments will be carried out near the exciton resonance using a second harmonic of a femtosecond Ti:Sapphire laser. These experiments will be performed varying intensity, polarization,and temperature on various samples grown under different conditions and on different substrates. In order to study the effect of polarity and band gap on the femtosecond nonlinearities, the femtosecond nonlinearities of GaN or InGaN will be investigated. The effect of changing the band gap on the femtosecond nonlinearities will be isolated by performing four- wave mixing experiments under pressure in a diamond anvil cell. The collaborators expect to obtain a coherent picture of femtosecond nonlinearities of wide bandgap materials through these and other novel experiments. Through their investigations, the collaborators will expand the frontiers of knowledge of the selected classes of semiconductor materials, some of which may have useful electronic applications. The collaborators have considerable complementary research experience in the field of their proposed project. This project is relevant to the objectives of the U.S.-Korea Cooperative Science Program which seeks to increase the level of cooperation between U.S. and Korean scientists and engineers through the exchange of scientific information, ideas, skills, and techniques and through collaboration on problems of mutual benefit. Korean part icipation in the project is supported by the Korea Science and Engineering Foundation (KOSEF). ***