排序方式: 共有22条查询结果,搜索用时 15 毫秒
1.
2.
Engineered omnidirectional external-reflectivity spectra from one-dimensional layered interference filters 总被引:8,自引:0,他引:8
Yablonovitch E 《Optics letters》1998,23(21):1648-1649
Owing to optical refraction, external rays that are incident upon a high-refractive-index medium fall within a small internal cone angle. A one-dimensionally periodic Bragg structure can reflect over an angular acceptance range that is greater than the small internal refraction cone, if the internal refractive-index contrast is sufficient. Thus Winn et al. [Opt. Lett. (to be published)] charted the range of refractive indices at which omnidirectional external reflection occurs. A wide spectral gap requires a high-index contrast. It is proposed that, by chirping or grading the periodicity of the structure, one can cover an arbitrarily wide spectral range with only a modest index contrast and, furthermore, that arbitrary spectral shapes can be produced. The graded-periodicity approach requires only a modest index contrast, provided that the average refractive index is >2 . 相似文献
3.
4.
Controlling the Spontaneous Precipitation of Silver Nanoparticles in Sol-Gel Materials 总被引:1,自引:0,他引:1
Wu Pu-Wei Dunn Bruce Doan Vinh Schwartz Benjamin J. Yablonovitch Eli Yamane Masayuki 《Journal of Sol-Gel Science and Technology》2000,19(1-3):249-252
The mechanisms responsible for spontaneous silver precipitation in silver-doped sol-gel materials are identified. The chemistry of the solvent phase is found to be the critical factor in controlling this phenomenon. The addition of HCl as catalyst leads to the formation of AgCl and subsequent formation of silver upon light exposure. Another factor leading to silver precipitation is the reducing capability of methanol radicals. Silver precipitation is inhibited by simply washing out the pore solvents by a solvent exchange method. 相似文献
5.
6.
7.
8.
9.
Reported is the collisionless infrared multiphoton excitation of NO2 molecules initially prepared in an electronically excited state. From the shape of the infrared induced blue-shifted fluorescence spectrum the probability distribution P(n) for the net absorption of n photons has been deduced. 相似文献
10.