Cross spectral purity and its influence on ghost imaging experiments

Pseudo-thermal light has been widely used in ghost imaging experiments. In order to understand the differences between the pseudo-thermal source and thermal source, we propose a method to investigate whether a light source has cross spectral purity (CSP), and experimentally measure the cross spectral properties of the pseudo-thermal light source in near-field and far-field zones. Moreover we present a theoretical analysis of the cross spectral influence on ghost imaging. (c) 2006 Elsevier B.V. All rights reserved.

Ultranarrow absorptive spectral line induced by microwave field

This paper investigates the absorptive spectral lines of four-level atomic system driven by a coupling, probe and microwave fields. Due to the perturbation of the microwave field, the original electromagnetically induced transparency is changed to electromagnetically induced absorption and the absorptive spectral line can be very narrow. This ultranarrow spectral line has potential applications to the microwave atomic frequency standard and the measurement of very weak magnetic field.

Crystal growth and optical properties of Gd1.99-xYxCe.0.01SiO5 single crystals

Gd1.99-xYxCe0.01SiO5 (Ce:GYSO) crystals (x = 0, 0.0995, 0.199) have been grown by the Czochralski (Cz) method. Crystal structure and the distribution coefficients of Ce have been determined for all three crystals. Spectroscopic measurements indicate that optical transmittance and luminescence intensity of Gd1.99-xYxCe0.01SiO5 (x = 0.0995, 0.199) crystals are Substantially higher than those of Ce:Gd2SiO5 (Ce:GSO), especially at x = 0.0995, which makes them good candidate materials for scintillation applications. The particularly important result is that the alloyed Ce:GYSO crystals can be grown easily by the Cz method and, unlike Ce:GSO, they do not undergo cleavage during the growth process or subsequent mechanical treatment. (c) 2005 Elsevier B.V. All rights reserved.

平板偏振膜的角度特性研究

当入射光倾斜入射到平板偏振膜上时，在两种偏振光的反射带边缘处出现P偏振光高透而S偏振光高反的情况．利用F-P结构的膜系设计了偏振膜．随着入射角的增大，S光的带宽、消光比及参考波长线性增大。而膜层中电场强度的最大值和界面处的电场强度均减小，只有P偏振光的变化特性跟布儒斯特角有关．分析膜层的界面特性和膜层中的缺陷分布情况，可得偏振膜P偏振光的阈值随入射角的增大而增大．结果表明。在P光透过率可使用的范围内，入射角越大，消光比越大，场强在膜层中的分布越低，但P偏振光的透过率有所降低．