中国科学院机构知识库网格系统: 检索

The application of symmetrical equation of diffracted wavevectors in integral theory of gratings (EI CONFERENCE) 会议论文 OAI收割
2nd International Conference on Advanced Engineering Materials and Technology, AEMT 2012, July 6, 2012 - July 8, 2012, Zhuhai, China
作者: Gao J.; Zhang F.; Zhang F.

收藏 | 浏览/下载：18/0 | 提交时间：2013/03/25

The integral theory for electromagnetic theory of gratings which has complex mathematical tool and long computation cost is needed to improve computing speed of the algorithm. A very shot-cut equation which is called symmetrical equation of diffracted wavevectors by us is presented. It makes the number of Green's function expansion terms shorter and simplifies the integral kernel by taking into account its symmetry. Take the grating in Littrow mount for computing example because of applying this equation the computation cost of integral theory which has good convergence is shorten to 1/2 to 2/5. This work modifies the integral theory and improves its computing speed. (2012) Trans Tech Publications Switzerland.

An embedded infrared image enhancement system based on DSP and FPGA (EI CONFERENCE) 会议论文 OAI收割
2012 International Conference on Manufacturing Engineering and Process, ICMEP 2012, April 21, 2012 - April 22, 2012, Kunming, China
作者: Zhang T.

收藏 | 浏览/下载：46/0 | 提交时间：2013/03/25

According to the disadvantage of the large noises of histogram equalization algorithm a new adaptive image enhancement algorithm is presented. First the statistical histogram of the infrared image is done. Then the threshold of plateaus Equalization is calculated and the statistical histogram is modified. Finally the bright values of the pixels of the image are changed. An embedded high speed image enhancement processing system on high performance DSP TMS320DM642 and FPGA was designed. Experimental results with real images shown that the system can improve the contrast of the infrared image limit the noises of the enhancement image and effectively enhance the infrared image the running time of the program is shorter so it can meet the requirements of real-time in the project. (2012) Trans Tech Publications.

Reflective foveated optical imaging system based on liquid crystal spatial light modulator (EI CONFERENCE) 会议论文 OAI收割
Optical Design and Testing IV, October 18, 2010 - October 20, 2010, Beijing, China
Peng Q.-Q.; Chang J.; Feng S.-L.; Wang R.-R.

收藏 | 浏览/下载：31/0 | 提交时间：2013/03/25

Based on reflective liquid crystal spatial light modulator (SLM) a new foveated optical imaging system is proposed. High quality imaging can be realized at any region of interest (ROI) within the field-of-view (FOV) by utilizing the SLM to correct the aberration of different regions dynamically. A reflective cassegrain optical structure is proposed which is designed optimized and matched with the reflective SLM to construct a more practical foveated imaging system. This reflective imaging system has a large aperture so that enough light can reach the image plane. It also makes the total length of the system shorter and therefore more practical. We also simulate and analyze the system. This kind of foveated optical imaging system can be applied in wide FOV imaging aspects to reduce bandwidth and optics complexity and to achieve weight reduction and miniaturization. 2010 Copyright SPIE - The International Society for Optical Engineering.

Experiments of second harmonic generation output in pulsed TEA CO 2 laser (EI CONFERENCE) 会议论文 OAI收割
High-Power Lasers and Applications V, October 18, 2010 - October 19, 2010, Beijing, China
作者: Li D.

收藏 | 浏览/下载：55/0 | 提交时间：2013/03/25

It is always the hot subject to realize the output of high-power laser in the range of 3-5m wavelength. This rang of wave band has greatly important applications in military because it located in the atmosphere window. Generally there are two ways to obtain this range of laser wavelength. One way is through optical parameter oscillation (OPO) from shorter laser wavelength and the other is through second harmonic generation (SHG) from longer laser wavelength. Firstly the comparison between tow nonlinear crystals ZnGeP2 and AgGaSe2 is conducted for their nonlinear coefficient and damaging threshold in theory. The theoretical results show that the crystal AgGaSe 2 is more suitable for the SHG of pulsed TEA CO2 laser. When using pulsed TEA CO2 laser with wavelength of 9.3m to pumping AgGaSe2 SHG crystal the wavelength of 4.65m is obtained. In the condition of repetition rate 100Hz the upmost output power of single pulse is up to level of 1W which corresponding efficiency of SHG is about 6%. The experimental results show that the polarization of laser beam has greatly influence on the SHG output of the crystal. Under the radiation of 3MW/cm 2 from fundamental wave and the right position for maximal SHG output in the crystal when polarization of laser beam rotates 4.5 the SHG output of energy decrease about 30%. The research of this paper will make a foundation for further development of mid-infrared laser. 2010 Copyright SPIE - The International Society for Optical Engineering.

Micro-motion exposure method based on PZT piezoelectric ceramics (EI CONFERENCE) 会议论文 OAI收割
International Symposium on Photoelectronic Detection and Imaging 2009: Material and Device Technology for Sensors, June 17, 2009 - June 19, 2009, Beijing, China
作者: Meng Z.; Meng Z.

收藏 | 浏览/下载：103/0 | 提交时间：2013/03/25

There mainly is laser digital photofinishing technique and digital photofinishing technique based on LCD consisting of TFT and LCOS in the digital photofinishing field at the present time. The former have a good many merit such as wide color gamut high processing rate large output size and high brightness but his cost is very high his maintain technique being comparatively complex that result in difficult use for people. The utilization ratio of the latter is low because of lower resolution and lower aperture ratio for LCD but the digital photofinishing based on LCD have lower cost and higher utilization ration being suitable for people's current standard of living. Considering above mentioned problem a micro-motion exposure method based on PZT piezoelectric ceramics used in digital image photofinishing is presented. The two-dimension micro-motion exposure system consisting of PZT piezoelectric ceramics LCD panel polarizing film and spring strip is designed. By means of PZT piezoelectric ceramics the LCD panel is removed about the one half of the pixel size of the LCD panel for four times from the original place at the same time imaging system is exposed four times at the printing paper. The software is used to control the time synchronization the exposure time and motion range of the LCD panel. The system has advantages such as shorter response time than 0.1seconds lesser motion error than 0.01 microns high stability and repeatability. Experimental results show that the proposed micro-motion exposure method improve the picture brightness and enlarge output size at the meantime reducing the cost of the system. 2009 SPIE.

High power 1064nm laser diode array and measuring chip temperature based on emitting spectra (EI CONFERENCE) 会议论文 OAI收割
Optoelectronic Materials and Devices III, October 27, 2008 - October 30, 2008, Hangzhou, China
作者: Wang X.; Wang L.; Wang L.; Wang L.; Wang Y.

收藏 | 浏览/下载：21/0 | 提交时间：2013/03/25

High power laser diode array with an emission wavelength of 1064nm is presented. The epitaxial structure is an InGaAs/GaAsP strained-compensated single-quantum well structure. The modules CW output power can reach to 56.5W at current of 80A. Because the heat capacity of st rather shorter pulse duration and lower duty cycle the average driving power in the laser chip is quite low so the heating effect cemiconductor laser is very small using pulse injection can reduce temperature rising significantly. Aould be neglected. The definite relation between lasing wavelength and chip temperature is developed. The temperature drift coefficient is 0. 45nm/K 2008 SPIE.

Optimization of multi-cycle two-color laser fields for the generation of an isolated attosecond pulse 期刊论文 OAI收割
opt. express, 2008, 卷号: 16, 期号: 14, 页码: 10331, 10340
Kim Byunghoon; Ahn Jungkwen; Yu Yongli; 程亚; 徐至展; Kim Dong Eon

收藏 | 浏览/下载：1093/55 | 提交时间：2009/09/18

America Attosecond pulses Full Width Half Maximum (FWHM) FWHM pulse Main color Mixing ratios Multi-cycle Optical (PET) (OPET) Optimal wavelength Pulse duration (PD) Shorter wavelengths Two color laser fields Two-color Two-dimensional (2D) map

Study of the fabrication of ZnO-TFT (EI CONFERENCE) 会议论文 OAI收割
Asia Display 2007, AD'07, March 12, 2007 - March 16, 2007, Shanghai, China
作者: Wang C.

收藏 | 浏览/下载：29/0 | 提交时间：2013/03/25

Znic Oxide (ZnO) as a shorter wavelength luminescent material concerning its outstanding properties of a wide band-gap semiconductor it can be used as the active channel layer to fabricate thin film transistor (TFT) and transparent thin film transistor(TTFT). In this paper we introduced ZnO-TFT using different substrate material insulator material electrode material of gate source and drain in its device.

Optical characterization of bare CdSe and CdSe/CdS core/shell nanocrystals (EI CONFERENCE) 会议论文 OAI收割
ICO20: Biomedical Optics, August 21, 2005 - August 26, 2005, Changchun, China
作者: Liu L.; Yu B.; Liu L.

收藏 | 浏览/下载：19/0 | 提交时间：2013/03/25

Thiol-capped CdSe/CdS core/shell nanocrystals (NCs) which show high luminescence quantum yield are synthesized in an aqueous solution. UV-Vis absorption spectroscopy and photoluminescence (PL) spectroscopy are employed to analyze optical characters and stabilities of NCs. Furthermore PL properties are studied in a temperature range between 77K and 300K. The PL peak position of bare CdSe NCs shifts toward shorter wavelengths and the band becomes sharper with decreasing temperature. On the same condition the PL peak position of CdSe/CdS core/shell NCs keeps unconverted nearly with the variation of temperature. Photostability of bare CdSe NCs and CdSe/CdS core/shell NCs are compared under the 325nm laser irradiation. It takes 78 seconds that the PL intensity declines to the half for CdSe NCs but 442 seconds for CdSe/CdS core/shell NCs. The fluorescence decay lifetime increases about six times after overcoating. The results indicate that the CdS shell can improve the low temperature PL stability and photostability of CdSe NCs effectively.

The study on the temperature influence of the grain near infrared spectrum analysis (EI CONFERENCE) 会议论文 OAI收割
ICO20: Optical Information Processing, August 21, 2005 - August 26, 2005, Changchun, China
作者: Zhang J.; Chen X.; Chen X.; Chen X.; Zhang J.

收藏 | 浏览/下载：26/0 | 提交时间：2013/03/25

Near-infrared spectroscopy was used to examine unmodified wheat powder at temperatures of 14-65C. A self-regulating diffuse reflected assembly was used to permit collection of spectra of powder samples. Changes to the shape and peak location of the 1400-1500nm and 1900-1950nm water absorption bands 2000-2050 2070-2110 and 2250-2300nm bands were measured as temperature varied. Results indicated that temperature changes resulted in slight changes to the water absorption bands in 1400-1500nm and 1900-1950nm regions. From 14-65C the 1400-1500nm and 2050-2150nm band shifted approximately 10nm and 16nm toward shorter wavelengths and 2000-2050nm band shifted approximately 14nm toward longer wavelengths. In addition few numbers of samples cannot constitute good temperature insensitive calibration model even though the spectra were obtained at wide temperature condition.