Electron–phonon coupling in topological insulator Bi_2Se_3 thin films with different substrates

Broadband transient reflectivity traces were measured for Bi_2 Se_3 thin films with various substrates via a 400 nm pump–white-light-probe setup. We have verified the existence of a second Dirac surface state in Bi_2 Se_3 and qualitatively located it by properly analyzing the traces acquired at different probe wavelengths. Referring to the band structure of Bi_2 Se_3, the relaxation mechanisms for photo-excited electrons with different energies are also revealed and studied. Our results show a second rise of the transient reflection signal at the time scale of several picoseconds. The types of substrate can also significantly affect the dynamics of the rising signal. This phenomenon is attributed to the effect of lattice heating and coherent phonon processes. The mechanism study in this work will benefit the fabrication of high-performance photonic devices based on topological insulators.     

Temperature insensitive multi-channel light amplification systems on SOI platform

We present a theoretical analysis of a novel multi-channel light amplification photonic system on chip, where the nonlinear Raman amplification phenomenon in the silicon(Si) wire waveguide is considered. Particularly, a compact and temperature insensitive Mach±Zehnder interferometer filter working as demultiplexer is also exploited, allowing for the whole Si photonic system to be free from thermal interference. The propagation of the multi-channel pump and Stokes lights is described by a rigorou...     

掺稀土光纤的光子暗化研究进展

掺稀土光纤是光纤激光器的基础,而掺杂光纤的光子暗化是影响激光输出功率稳定性的重要因素。综述了光子暗化的产生机理、光子暗化对光纤激光器的影响及其抑制方法,旨在为相关研究提供参考。