Design of cooled medium-wave infrared polarization imaging optical system

2021 ◽  
Vol 50 (2) ◽  
pp. 20200208-20200208
Author(s):  
刘星洋 Xingyang Liu ◽  
翟尚礼 Shangli Zhai ◽  
李靖 Jing Li ◽  
汪洋 Yang Wang ◽  
苗锋 Feng Miao ◽  
...  
2019 ◽  
Vol 48 (4) ◽  
pp. 418006
Author(s):  
尹 骁 Yin Xiao ◽  
李英超 Li Yingchao ◽  
史浩东 Shi Haodong ◽  
江 伦 Jiang Lun ◽  
王 超 Wang Chao ◽  
...  

2021 ◽  
Vol 50 (2) ◽  
pp. 20200208-20200208
Author(s):  
刘星洋 Xingyang Liu ◽  
翟尚礼 Shangli Zhai ◽  
李靖 Jing Li ◽  
汪洋 Yang Wang ◽  
苗锋 Feng Miao ◽  
...  

2019 ◽  
Vol 40 (5) ◽  
pp. 717-722
Author(s):  
LIU Qingqing ◽  
JU Caihua ◽  
MING Mei

Author(s):  
Michel Troyonal ◽  
Huei Pei Kuoal ◽  
Benjamin M. Siegelal

A field emission system for our experimental ultra high vacuum electron microscope has been designed, constructed and tested. The electron optical system is based on the prototype whose performance has already been reported. A cross-sectional schematic illustrating the field emission source, preaccelerator lens and accelerator is given in Fig. 1. This field emission system is designed to be used with an electron microscope operated at 100-150kV in the conventional transmission mode. The electron optical system used to control the imaging of the field emission beam on the specimen consists of a weak condenser lens and the pre-field of a strong objective lens. The pre-accelerator lens is an einzel lens and is operated together with the accelerator in the constant angular magnification mode (CAM).


Author(s):  
Marcos F. Maestre

Recently we have developed a form of polarization microscopy that forms images using optical properties that have previously been limited to macroscopic samples. This has given us a new window into the distribution of structure on a microscopic scale. We have coined the name differential polarization microscopy to identify the images obtained that are due to certain polarization dependent effects. Differential polarization microscopy has its origins in various spectroscopic techniques that have been used to study longer range structures in solution as well as solids. The differential scattering of circularly polarized light has been shown to be dependent on the long range chiral order, both theoretically and experimentally. The same theoretical approach was used to show that images due to differential scattering of circularly polarized light will give images dependent on chiral structures. With large helices (greater than the wavelength of light) the pitch and radius of the helix could be measured directly from these images.


Author(s):  
B. Roy Frieden

Despite the skill and determination of electro-optical system designers, the images acquired using their best designs often suffer from blur and noise. The aim of an “image enhancer” such as myself is to improve these poor images, usually by digital means, such that they better resemble the true, “optical object,” input to the system. This problem is notoriously “ill-posed,” i.e. any direct approach at inversion of the image data suffers strongly from the presence of even a small amount of noise in the data. In fact, the fluctuations engendered in neighboring output values tend to be strongly negative-correlated, so that the output spatially oscillates up and down, with large amplitude, about the true object. What can be done about this situation? As we shall see, various concepts taken from statistical communication theory have proven to be of real use in attacking this problem. We offer below a brief summary of these concepts.


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