Two-photon lasers require materials with large two-photon gain (2PG) coefficients and low linear and nonlinear losses. Our previous demonstration of large enhancement of two-photon absorption in semiconductors for very different photon energies translates directly into enhancement of 2PG. We experimentally demonstrate nondegenerate 2PG in optically excited bulk GaAs via femtosecond pump-probe measurements. 2PG is isolated from other pump induced effects through the difference between measurements performed with parallel and perpendicular polarizations of pump and probe. An enhancement in the 2PG coefficient of nearly two orders-of-magnitude is reported. The results point a possible way toward two-photon semiconductor lasers.
Metamaterial control of stimulated Brillouin scattering
使用完整的光声数值模拟，我们证明了增强和抑制的SBS增益的超材料，包括一个亚波长立方阵列的介电球悬浮在介电背景材料。我们开发了一个一般的理论框架，并提出了几个数值例子，使用技术上重要的材料。对于硅中的As $_2$ S $_3$球，与纯硅相比，我们实现了超过一个数量级的增益增强，并且对于硅中的GaAs球，获得了完全抑制。As $_2$ S $_3$玻璃的增益也可以通过嵌入二氧化硅球来强烈抑制。示出的增益系数的组成项依赖于在一个复杂的方式上的填充分数。我们发现电致伸缩是体相介质中SBS控制的主要效应。
Nonlinear-linear duality for multipath quantum interference
University of Science and Technology of China（中国科学技术大学）；Laboratory of Quantum Information, University of Science and Technology of China（中国科学技术大学量子信息实验室）；Anhui Province Key Laboratory of Quantum Network, University of Science and Technology of China（中国科学技术大学安徽省量子网络重点实验室）；CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China（中国科学技术大学中国科学院量子信息与量子物理前沿卓越创新中心）；Hefei National Laboratory, University of Science and Technology of China（中国科学技术大学合肥国家实验室）
Few-picosecond pulse generation featuring ultrafast spectral dynamics in gain-switched surface-grating DFB lasers via impulsive optical pumping
Institute for Solid State Physics, The University of Tokyo（东京大学固体物理研究所）；State Key Laboratory of Precision Spectroscopy, Department of Electronic Engineering, East China Normal University（华东师范大学精密光谱科学国家重点实验室电子工程系）；LDseed Co., Ltd.（LDseed有限公司）
