Yuanhe Tang,^1,2,* Xiangang Cao,¹ Hanchen Liu,³ G. G. Shepherd,² Shulin Liu,⁴ Haiyang Gao,¹ Xusan Yang,¹ Yong Wu,¹ and Shuiwei Wang¹

¹School of Science, Xi’an University of Technology, No. 5 South Jinhua Road, Xi’an 710048, China
²Centre for Research in Earth and Space Science, York University, 4700 Keele Street, Toronto, Ontario, Canada, M3J 1P3
³School of Science, Xi’an Polytechnic University, Xi’an 710048, China
⁴Xi’an Branch, North Night Vision Technology Co. Ltd., Xi’an 710065, China
*Corresponding author: ltp1801@163.com

In order to obtain information both of aurora and airglow in one image by the same detector, a PLCI based on liquid crystal plate LCP and super second-generation image intensifier SSGII is proposed in this research.The detection thresholds of the CCD for aurora and airglow are calculated. For the detectable illumination range of 10⁴–10−²lx, the corresponding electron count is 1.57 × 10⁵ − 0.2 for every pixel of CCD. The structure and work principle of the PLCI are described. An LC is introduced in the front of CCD
to decrease the intensities of aurora in overexposure areas by means of controlling transmittances pixel by pixel, while an image intensifier is set between the LC and CCD to increase the intensity of the weak airglow. The modulation transfer function MTF of this system is calculated as 0.391 at a Nyquist frequency of 15 lp∕mm. The curve of transmittance with regard to gray level for the LC is obtained by calibration experiment. Based on the design principle, the prototype is made and used to take photos of objects under strong light greater than 2 × 10⁵ lx. The clear details of “西安理工大学XauT ” presented in the image indicate that the PLCI can greatly improve the imaging quality. The theoretical calculations and experiment results prove that this device can extend the dynamic range and it provides a more effective method for upper atmospheric wind measurement. © 2012 Optical Society of America OCIS codes: 120.4570, 110.2970, 010.0280, 230.3720.

Partially light-controlled imager based on liquid crystal plate and image intensifier for aurora and airglow measurement.pdf

Subluminal to superluminal light propagation in a V-type three-level atomic system with  squeezed vacuum∗

Zhang Qin（张琴）^a）＋ , Qu Guang-Hui （屈光辉）^a） ,Tang Yuan-He（唐远河）^a）,Jin Kang（金康）^b）,and Ji Wei-Li（纪卫莉）^a）

a)Department of Physics , Xi’an University of Technology, Xi’an 710054, China
b)Department of Physics, Northwest University, Xi’an 710069, China
(Received 14 July 2011; revised manuscript received 29 August 2011)

We study the light propagation properties in a V-type three-level atomic system interacting with two independent broadband squeezed baths. Using the graphic method, the dependences of the absorption and the dispersion of the system on the coupling field strength, the incoherent pumping field strength and the intensity of the squeezed vacuum
are analysed. The result shows that the probe pulse propagation can be changed from subluminal to superluminal speed.

Keywords: squeezed vacuum, group velocity, superluminal propagation, subluminal propagation

Subluminal to superluminal light propagation in a V-type three-level atomic system interacting with squeezed vacuum.pdf

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