A new concept of theoretical resolution of an optical system, comparison with experiment and optimum condition for a point source

1992 ◽  
Vol 41 (1-3) ◽  
pp. 181-192 ◽  
Author(s):  
M. Sato ◽  
J. Orloff
Keyword(s):  
Optimum Condition ◽  
Point Source ◽  
Optical System ◽  
Comparison With Experiment

scholarly journals LENS OF AN OPTICAL ELECTRONIC SYSTEM WITH PROTECTION OF PHOTO-RECEPTION DEVICE FROM DAMAGING EFFECTS OF BRIGHT RADIATION POINT SOURCE

2019 ◽  
Vol 8 ◽  
pp. 298-306
Author(s):  
Igor Mikhailov ◽  
Tatyana Khatsevich
Keyword(s):  
Point Source ◽  
Optical System ◽  
Optoelectronic Devices ◽  
Bright Light ◽  
Electronic System ◽  
Laser Source ◽  
Light Pulses ◽  
Radiation Sources ◽  
Protection Systems ◽  
Damaging Effects

The article considers the relevance of the development of protection systems for human eye and photodetectors of modern optoelectronic devices from the damaging effects of bright light pulses of extended and point radiation sources. The optical system of a lens with protection of photo-reception device from a powerful flash point laser source of radiation is suggested.

Properties of dual parabolic cylindrical reflectors

1985 ◽  
Vol 63 (10) ◽  
pp. 1299-1305 ◽  
Author(s):  
M. S. A. Sanad ◽  
L. Shafai
Keyword(s):  
Point Source ◽  
Optical System ◽  
Integration Method ◽  
The Other ◽  
Main Beam ◽  
Far Field ◽  
Beam Direction ◽  
System Parameters ◽  
Focal Line ◽  
Field Patterns

Two parabolic cylinders having the focal line of one coincident with the directrix of the other form an optical system that focuses the focal line of the first reflector to a point at infinity. The operation principle of such a system is studied, and its far diffracted field is determined. The unit is assumed to be illuminated by a directional point source, simulating a feed horn, and a ray-tracing approach is used to obtain the reflected and main diffracted fields over its aperture. The far-field patterns in the vicinity of the main beam direction are then computed by an aperture-integration method. The effects of various system parameters, on the far-field patterns, are also determined.

scholarly journals Structure of image fields in an aplanatic optical system with coherent point source illumination

2007 ◽  
Vol 56 (2) ◽  
pp. 811
Author(s):  
Guo Han-Ming ◽  
Chen Jia-Bi ◽  
Zhuang Song-Lin
Keyword(s):  
Point Source ◽  
Optical System ◽  
Source Illumination

The Distribution of Light from Optical Systems

1949 ◽  
Vol 2 (3) ◽  
pp. 335
Author(s):  
WH Steel
Keyword(s):  
Point Source ◽  
Optical System ◽  
Optical Axis ◽  
Spherical Aberration ◽  
Light Distribution ◽  
Optical Systems ◽  
Geometrical Method ◽  
Plane Normal ◽  
Finite Source

A geometrical method is developed for calculating the distribution of intensity with angle of the light leaving an optical system, when the angle at which a ray from a point on the optical axis leaves the system is known as a function of the aperture. The case of a point source on the axis of the system is treated exactly, and an approximation is given for that of a small finite source ; the method is applicable to systems with spherical aberration. The distribution of illumination across any plane normal to the axis is treated by analogous methods. The results are compared with measurements of the light distribution from an optical system possessing considerable spherical aberration.

Optical Performance of a Laser Point Source Strongly Emitted by an Aspheric Expander

2012 ◽  
Vol 497 ◽  
pp. 304-310
Author(s):  
Song Chon Park ◽  
Toshiro K. Doi ◽  
Syuhei Kurokawa ◽  
Osamu Ohnishi
Keyword(s):  
Point Source ◽  
Optical System ◽  
Optical Design ◽  
Optical Performance ◽  
Power Performance ◽  
Design Data ◽  
Beam Expander ◽  
Good Uniform ◽  
Full Power ◽  
The Given

We composed optical system which is made of two optical lenses, beam expander, and Laser Diode(LD). When the light from the LD pointed to the remote moving object, we optically aligned to achieve full power performance in the given angle range. We also reviewed optical design data with Light Tools, and measured some factors including LD cell, surface roughness and refringence. The result shows that the laser point source optical system displayed good uniform power shape, and the LD used for this experiment to be guaranteed superior output power performance compared to conventional specifications.

A Field Emission System For Transmission Electron Microscopy

1973 ◽  
Vol 31 ◽  
pp. 298-299
Author(s):  
Michel Troyonal ◽  
Huei Pei Kuoal ◽  
Benjamin M. Siegelal
Keyword(s):  
Electron Microscope ◽  
Field Emission ◽  
Optical System ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Objective Lens ◽  
Electron Optical System ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Emission System

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).

New type electron gun with electrostatic and electromagnetic lenses

1978 ◽  
Vol 36 (1) ◽  
pp. 62-63
Author(s):  
T. Ichinokawa ◽  
H. Maeda
Keyword(s):  
Electron Microscopy ◽  
Electron Beam ◽  
Optimum Condition ◽  
Bias Voltage ◽  
Electron Gun ◽  
Charge Effect ◽  
Micro Fabrication ◽  
Maximum Brightness ◽  
New Type ◽  
The Ideal

I. IntroductionThermionic electron gun with the Wehnelt grid is popularly used in the electron microscopy and electron beam micro-fabrication. It is well known that this gun could get the ideal brightness caluculated from the Lengumier and Richardson equations under the optimum condition. However, the design and ajustment to the optimum condition is not so easy. The gun has following properties with respect to the Wehnelt bias; (1) The maximum brightness is got only in the optimum bias. (2) In the larger bias than the optimum, the brightness decreases with increasing the bias voltage on account of the space charge effect. (3) In the smaller bias than the optimum, the brightness decreases with bias voltage on account of spreading of the cross over spot due to the aberrations of the electrostatic immersion lens.In the present experiment, a new type electron gun with the electrostatic and electromagnetic lens is designed, and its properties are examined experimentally.

Information and estimation in image processing

1987 ◽  
Vol 45 ◽  
pp. 14-17
Author(s):  
B. Roy Frieden
Keyword(s):  
Image Processing ◽  
Optical System ◽  
Large Amplitude ◽  
Communication Theory ◽  
Image Data ◽  
Direct Approach ◽  
Ill Posed

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.

XRMF applications of a monolithic, polycapillary, focusing x-ray optic

1996 ◽  
Vol 54 ◽  
pp. 240-241
Author(s):  
D. A. Carpenter ◽  
Ning Gao ◽  
G. J. Havrilla
Keyword(s):  
Trace Elements ◽  
Point Source ◽  
Focal Spot ◽  
Fluorescence Analysis ◽  
X Rays ◽  
Focal Distance ◽  
Spot Diameter ◽  
X Ray ◽  
Focal Spot Diameter

A monolithic, polycapillary, x-ray optic was adapted to a laboratory-based x-ray microprobe to evaluate the potential of the optic for x-ray micro fluorescence analysis. The polycapillary was capable of collecting x-rays over a 6 degree angle from a point source and focusing them to a spot approximately 40 µm diameter. The high intensities expected from this capillary should be useful for determining and mapping minor to trace elements in materials. Fig. 1 shows a sketch of the capillary with important dimensions.The microprobe had previously been used with straight and with tapered monocapillaries. Alignment of the monocapillaries with the focal spot was accomplished by electromagnetically scanning the focal spot over the beveled anode. With the polycapillary it was also necessary to manually adjust the distance between the focal spot and the polycapillary.The focal distance and focal spot diameter of the polycapillary were determined from a series of edge scans.

Atomic Resolution in Crystal Aperture Stem

1990 ◽  
Vol 48 (1) ◽  
pp. 236-237
Author(s):  
J T Fourie
Keyword(s):  
Optical System ◽  
Spherical Aberration ◽  
Three Dimensional ◽  
Transmission Function ◽  
Optical Systems ◽  
Bragg Angle ◽  
Electron Optical System ◽  
Intimate Contact ◽  
Diffraction Effects ◽  
Design Aspect

The attempts at improvement of electron optical systems to date, have largely been directed towards the design aspect of magnetic lenses and towards the establishment of ideal lens combinations. In the present work the emphasis has been placed on the utilization of a unique three-dimensional crystal objective aperture within a standard electron optical system with the aim to reduce the spherical aberration without introducing diffraction effects. A brief summary of this work together with a description of results obtained recently, will be given.The concept of utilizing a crystal as aperture in an electron optical system was introduced by Fourie who employed a {111} crystal foil as a collector aperture, by mounting the sample directly on top of the foil and in intimate contact with the foil. In the present work the sample was mounted on the bottom of the foil so that the crystal would function as an objective or probe forming aperture. The transmission function of such a crystal aperture depends on the thickness, t, and the orientation of the foil. The expression for calculating the transmission function was derived by Hashimoto, Howie and Whelan on the basis of the electron equivalent of the Borrmann anomalous absorption effect in crystals. In Fig. 1 the functions for a g220 diffraction vector and t = 0.53 and 1.0 μm are shown. Here n= Θ‒ΘB, where Θ is the angle between the incident ray and the (hkl) planes, and ΘB is the Bragg angle.

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