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Yi J.,Heilongjiang University | An L.M.,Heilongjiang University | Han X.T.,Heilongjiang University | Liu C.X.,Heilongjiang University | And 2 more authors.
2012 Symposium on Photonics and Optoelectronics, SOPO 2012

Thiol-capped CdSe quantum dots are synthesized rapidly in aqueous solution assisted by microwave irradiation without any poisonous materials. The growth rate of quantum dots is greatly enhanced in this current microwave synthesis. The narrow size distribution (∼30nm) of CdSe quantum dots is similar to the oil samples. The results indicate that the photoluminescence quality of quantum dots is improved effectively assisted by microwave irradiation compared to traditional aqueous solution. Room and low temperature photoluminescence is employed to investigate the excitonic emission from thiol-capped CdSe quantum dots between 83K and 300K. The photoluminescence peak position of CdSe quantum dots shift to shorter wavelengths. The relationship between the shift wavelengths and the temperature is linear. The slope for linear fitting curve is nearly constant in repeated experiment. This implies CdSe quantum dots may be applied in the low temperature nano-sensor. The photoluminescence intensity first enhances and then quench with decrease of temperature. The temperature dependence of the photoluminescence intensity is demonstrated through thermal escape and thermal rectification of surface trap states. © 2012 IEEE. Source

Zhu H.-R.,PLA Navy Submarine Academy | Zhu H.,PLA Navy Submarine Academy | Liu J.-T.,Ocean University of China | Wen Y.-N.,Qingdao Academy for Opto electronics Engineering | Li W.-Y.,PLA Navy Submarine Academy
Guangxue Jingmi Gongcheng/Optics and Precision Engineering

To realize the real-time measurement of optical concealment depth for a vehicle under water, an optical concealment depth measurement system for the underwater vehicle was developed. According to the target background contrast transfer theory, the transport properties of the target background contrast in sea water, air and sea were analyzed and a model of underwater optical concealment depth for the vehicle was established. On the basis of the model, required parameters for measuring optical concealment depth of underwater vehicle were analyzed and the measuring methods for the water upward irradiance, water downward irradiance, water body attenuation coefficients, water diffuse attenuation coefficients and underwater vehicle surface reflectivity were designed. Then, an experiment on sea was completed, and it shows that underwater optical concealment depth of the vehicle with a characteristic scale of 12 m ranges from 25 m to 35 m under good weather conditions. The experimental results indicate that the measurement system successfully measures the depth of optical concealment of the vehicle and also is suitable for other submarines. As it avoids the traditional depth measurement mode, the system has stable and reliable operation, improves the conceal ability and measuring accuracy, and provides the supports for underwater flight decision. © 2015, SCIENCE PRESS. All right reserved. Source

Qi M.-J.,Qingdao Academy for Opto electronics Engineering | Wang X.-Q.,Qingdao Academy for Opto electronics Engineering | Yu C.-R.,Qingdao Academy for Opto electronics Engineering | Pan D.-N.,Qingdao Academy for Opto electronics Engineering | Xia W.-W.,Qingdao Academy for Opto electronics Engineering
Guangxue Jingmi Gongcheng/Optics and Precision Engineering

A microscopic spectral imaging system was proposed based on a Liquid Crystal Tunable Filter (LCTF). The systemic structure principle and operating method were introduced and a prototype was developed. Using the idea of modular design, a spectral imaging module was developed to cooperate with a microscope by connecting a standard C switch interface and a microscopic video interface. The LCTF was used as light filter in the spectral imaging module to select the light of certain wavelength by an electrical tuning mode. Without moving parts in the system, it could offer a faster tuning speed and could select wavelength by programming in flexibility. Then, the LCTF was placed in the collimated path to eliminate the possible aberrations. Furthermore, the software for image collection and analysis was developed to perform the order control and data analysis for the spectral images. The prototype was completed and microscopic spectral imaging experiment was performed for hair fibers and longitudinal sections of pumpkin stem. The spectral images with wavelength varied from 400 nm to 720 nm in 10 nm intervals were obtained. The results show that different origins of hair fibers have been distinguished and also different parts of longitudinal sections of pumpkin stem are extracted. The proposed system completes microscopic spectral imaging and collects good quality data, by which the function and application areas of the traditional microscope have been extended. ©, 2015, Chinese Academy of Sciences. All right reserved. Source

Wen Y.,Qingdao Academy for Opto electronics Engineering | Tian W.,Qingdao Academy for Opto electronics Engineering | Zheng B.,Qingdao Academy for Opto electronics Engineering | Zhou G.,Qingdao Academy for Opto electronics Engineering | And 2 more authors.
Proceedings of SPIE - The International Society for Optical Engineering

Due to the absorptive and scattering nature of water, the characteristic of underwater image is different with it in the air. Underwater image is characterized by their poor visibility and noise. Getting clear original image and image processing are two important problems to be solved in underwater clear vision area. In this paper a new approach technology is presented to solve these problems. Firstly, an inhomogeneous illumination method is developed to get the clear original image. Normal illumination image system and inhomogeneous illumination image system are used to capture the image in same distance. The result shows that the contrast and definition of processed image is get great improvement by inhomogeneous illumination method. Secondly, based on the theory of photon transmitted in the water and the particularity of underwater target detecting, the characters of laser scattering on underwater target surface and spatial and temporal characters of oceanic optical channel have been studied. Based on the Monte Carlo simulation, we studied how the parameters of water quality and other systemic parameters affect the light transmitting through water at spatial and temporal region and provided the theoretical sustentation of enhancing the SNR and operational distance. © 2014 Copyright SPIE. Source

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