排序方式: 共有2条查询结果,搜索用时 0 毫秒
1
1.
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. 相似文献
2.
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... 相似文献
1