A theoretical study for femtosecond laser-induced ultrafast electro-absorption of bulk solids is presented.Our numerical results show that,in the case of low intensity of the pump laser where the interaction between t...A theoretical study for femtosecond laser-induced ultrafast electro-absorption of bulk solids is presented.Our numerical results show that,in the case of low intensity of the pump laser where the interaction between the pump laser and solids is in the multi-photon regime,the energy band of solids can be approximately taken as a parabolic band and electro-absorption spectrums from the parabolic band and real band are nearly the same.While,in the case of high intensity where the interaction is in the tunneling regime,spectrums from the parabolic band and real band are quite different.The physical mechanism for the difference in the tunneling regime is found.We find that the non-parabolic parts of the real energy band and Bragger scattering of electrons near the first Brillouin zone boundaries,which are neglected in previous studies,strongly influence the electro-absorption spectrum in the tunneling regime.These two physical processes cause the difference of spectrums.Our theoretical results are in accordance with the experiment result.展开更多
采用有限元COM SOL m u ltiphysics软件和耦合模理论,首先分析了微结构光纤B ragg光栅反射光谱特性,结果表明随着空气孔中的填充材料的折射率的增加,微结构光纤B ragg光栅反射峰波长向长波长方向漂移,其次分析了空气和酒精填充下微结构...采用有限元COM SOL m u ltiphysics软件和耦合模理论,首先分析了微结构光纤B ragg光栅反射光谱特性,结果表明随着空气孔中的填充材料的折射率的增加,微结构光纤B ragg光栅反射峰波长向长波长方向漂移,其次分析了空气和酒精填充下微结构光纤B ragg光栅温度传感特性,通过两者的模拟,寻找合适材料填充微结构光纤B ragg光栅,为高性能传感器方面的研究提供了参考依据。展开更多
Thermo-optic tunable thin-film filter based on Fabry-Perot(F-P) cavity structure is a very attractive alternative integrated optical device.In this simulation-based paper,the key performance of typical thermo-optic tu...Thermo-optic tunable thin-film filter based on Fabry-Perot(F-P) cavity structure is a very attractive alternative integrated optical device.In this simulation-based paper,the key performance of typical thermo-optic tunable F-P filter is discussed by analyzing the structure of Distributed Bragger Reflectors(DBR) and the thermo-optic property of cavity thin-film material.The results indicate a negative correlation between the number of DBR periodical layers and full width at half maximum(FWHM),and a proportional relation between thermal-optic coefficient of material and tuning range.In addition,the cavity is more sensitive to the optical property than the reflection layers according to the analysis of thickness error of the film.And to solve slow thermal response without incurring other performance loss,a novel structure of the suspended cavity is proposed,in which only the cavity is heated.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.61505023)
文摘A theoretical study for femtosecond laser-induced ultrafast electro-absorption of bulk solids is presented.Our numerical results show that,in the case of low intensity of the pump laser where the interaction between the pump laser and solids is in the multi-photon regime,the energy band of solids can be approximately taken as a parabolic band and electro-absorption spectrums from the parabolic band and real band are nearly the same.While,in the case of high intensity where the interaction is in the tunneling regime,spectrums from the parabolic band and real band are quite different.The physical mechanism for the difference in the tunneling regime is found.We find that the non-parabolic parts of the real energy band and Bragger scattering of electrons near the first Brillouin zone boundaries,which are neglected in previous studies,strongly influence the electro-absorption spectrum in the tunneling regime.These two physical processes cause the difference of spectrums.Our theoretical results are in accordance with the experiment result.
文摘采用有限元COM SOL m u ltiphysics软件和耦合模理论,首先分析了微结构光纤B ragg光栅反射光谱特性,结果表明随着空气孔中的填充材料的折射率的增加,微结构光纤B ragg光栅反射峰波长向长波长方向漂移,其次分析了空气和酒精填充下微结构光纤B ragg光栅温度传感特性,通过两者的模拟,寻找合适材料填充微结构光纤B ragg光栅,为高性能传感器方面的研究提供了参考依据。
基金supported by the National Basic Research Program of China ("973" Program) (Grant Nos. 2012CB315701 and 2012CB315702)the National Natural Science Foundation of China (Grant No. 61177035)the National High-Tech Research & Development Program of China ("863" Program) (Grant No.2011AA010300)
文摘Thermo-optic tunable thin-film filter based on Fabry-Perot(F-P) cavity structure is a very attractive alternative integrated optical device.In this simulation-based paper,the key performance of typical thermo-optic tunable F-P filter is discussed by analyzing the structure of Distributed Bragger Reflectors(DBR) and the thermo-optic property of cavity thin-film material.The results indicate a negative correlation between the number of DBR periodical layers and full width at half maximum(FWHM),and a proportional relation between thermal-optic coefficient of material and tuning range.In addition,the cavity is more sensitive to the optical property than the reflection layers according to the analysis of thickness error of the film.And to solve slow thermal response without incurring other performance loss,a novel structure of the suspended cavity is proposed,in which only the cavity is heated.
