Damage tests for 355 nm laser mirror by using a new variable spot size optical system (VariSpot)

2007 ◽  
Author(s):  
Constantin Fenic ◽  
Liviu Neagu ◽  
Cristian Viespe ◽  
Gheorghe Honciuc ◽  
George Nemeş
Keyword(s):  
Optical System ◽  
Spot Size ◽  
Laser Mirror

Design of an adjustable spot size laser cladding optical system

2020 ◽  
Author(s):  
Jiabao Zhang ◽  
Hua Fan ◽  
Xianghe Ren ◽  
Jing Wang ◽  
Zixin Yang
Keyword(s):  
Laser Cladding ◽  
Optical System ◽  
Spot Size

Analysis on Resolution Enhancement by Optical Pupil Apodization in a Laser Scanning Printing System

2016 ◽  
Author(s):  
Wan-chin Kim ◽  
Sang-Koo Han ◽  
Sung-Dae Kim
Keyword(s):  
Optical System ◽  
Laser Scanning ◽  
Focal Length ◽  
Resolution Enhancement ◽  
Focal Depth ◽  
Optical Resolution ◽  
Spot Size ◽  
Experimental Result ◽  
Entrance Pupil ◽  
High Degree

Apodization of amplitude and phase at the entrance pupil of an optical system is able to have advantages on optical resolution and focal depth. As an optical system for the electro-photography continuously requires highly resolved dot image and extended focal length to obtain more delicate expression with adequate production stability. Advantages from apodization technique can improve system performance and supply high degree of reliability of the optical system. In this study, theoretical apodization characteristics in a laser scanning optical system for electro-photography is firstly analyzed in the aspects of enhancement of optical resolution and focal depth with the proposed method of apodization. In addition, fundamental experimental result on measurement of beam spot size is reported to support theoretical results.

Minimal spot size on the retina formed by the optical system of the eye

1979 ◽  
Vol 1 (3) ◽  
pp. 175-178 ◽  
Author(s):  
R. Birngruber ◽  
E. Drechsel ◽  
F. Hillenkamp ◽  
V. -P. Gabel
Keyword(s):  
Optical System ◽  
Spot Size

scholarly journals Variable spot size optical system for a dual-wavelength laser therapy device

2020 ◽  
Vol 13 (04) ◽  
pp. 2050018
Author(s):  
Ningning Dong ◽  
Jinjiang Cui ◽  
Jiangen Xu
Keyword(s):  
Laser Therapy ◽  
Optical System ◽  
High Power ◽  
Spot Size ◽  
Dual Wavelength ◽  
High Power Laser ◽  
Power Laser ◽  
Dual Wavelength Laser ◽  
Beam Combination ◽  
532 Nm

The majority of existing high-power laser therapeutic instruments employ a single wavelength for a single target; thus, they do not meet the requirements for clinical treatment. Therefore, this study designs an optical system for a dual-wavelength high-power laser therapeutic device with a variable spot size. The waist of the short arm of the optical cavity and the G1G2 parameter (G-parameter equivalent cavity method) is calculated using MATLAB software, the spot size and divergence angle on the lens are calculated using an ABCD matrix, and the distance between the treatment spot at different spot sizes and the transformation lens is calculated in order to design the treatment handpiece. Experiments are conducted to analyze the stability at an output power of 532 nm before beam combination and the power loss after beam combination. The results show that the output power stability of the 532-nm beam varies by less than 2% over 150 min, and the loss of both wavelengths is less than 20%, which meets the clinical requirements of the system. The safety performance can meet the requirements of national general standards for medical electrical safety. The proposed dual-wavelength laser therapy instrument has both visible wave and near-infrared wave characteristics; thus, it can accurately target both superficial vessels and vessels with a larger diameter and deeper position. This therapeutic device has the advantages of simple operation, stable and reliable laser output, high security and strong anti-interference ability, and meets the comprehensive clinical treatment demands of vascular diseases.

scholarly journals Compound focusing mirror and X-ray waveguide optics for coherent imaging and nano-diffraction

2015 ◽  
Vol 22 (4) ◽  
pp. 867-878 ◽  
Author(s):  
Tim Salditt ◽  
Markus Osterhoff ◽  
Martin Krenkel ◽  
Robin N. Wilke ◽  
Marius Priebe ◽  
...  
Keyword(s):  
Optical System ◽  
Spot Size ◽  
High Gain ◽  
Beam Shaping ◽  
Biological Imaging ◽  
X Rays ◽  
Coherent Imaging ◽  
Characterization Methods ◽  
X Ray ◽  
Nano Imaging

A compound optical system for coherent focusing and imaging at the nanoscale is reported, realised by high-gain fixed-curvature elliptical mirrors in combination with X-ray waveguide optics or different cleaning apertures. The key optical concepts are illustrated, as implemented at the Göttingen Instrument for Nano-Imaging with X-rays (GINIX), installed at the P10 coherence beamline of the PETRA III storage ring at DESY, Hamburg, and examples for typical applications in biological imaging are given. Characteristic beam configurations with the recently achieved values are also described, meeting the different requirements of the applications, such as spot size, coherence or bandwidth. The emphasis of this work is on the different beam shaping, filtering and characterization methods.

Remarks on the application of backscattered electron imaging (BEI) to the scanning electron microscopy (SEM) of biological structures

1983 ◽  
Vol 41 ◽  
pp. 484-487
Author(s):  
Etienne de Harven
Keyword(s):  
High Resolution ◽  
Incident Beam ◽  
Spot Size ◽  
Primary Electron ◽  
Critical Point Drying ◽  
Cell Shapes ◽  
High Resolution Images ◽  
Backscattered Electron ◽  
Electron Imaging ◽  
Scanning Electron

Biological ultrastructures have been extensively studied with the scanning electron microscope (SEM) for the past 12 years mainly because this instrument offers accurate and reproducible high resolution images of cell shapes, provided the cells are dried in ways which will spare them the damage which would be caused by air drying. This can be achieved by several techniques among which the critical point drying technique of T. Anderson has been, by far, the most reproducibly successful. Many biologists, however, have been interpreting SEM micrographs in terms of an exclusive secondary electron imaging (SEI) process in which the resolution is primarily limited by the spot size of the primary incident beam. in fact, this is not the case since it appears that high resolution, even on uncoated samples, is probably compromised by the emission of secondary electrons of much more complex origin.When an incident primary electron beam interacts with the surface of most biological samples, a large percentage of the electrons penetrate below the surface of the exposed cells.

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).

A High Resolution Scanning Microscope

1968 ◽  
Vol 26 ◽  
pp. 356-357
Author(s):  
A. V. Crewe ◽  
J. Wall ◽  
L. M. Welter
Keyword(s):  
High Resolution ◽  
Field Emission ◽  
Spherical Aberration ◽  
Focal Length ◽  
Spot Size ◽  
Emission Source ◽  
Field Of View ◽  
Scanning Microscope ◽  
Magnetic Lens ◽  
High Quality

A scanning microscope using a field emission source has been described elsewhere. This microscope has now been improved by replacing the single magnetic lens with a high quality lens of the type described by Ruska. This lens has a focal length of 1 mm and a spherical aberration coefficient of 0.5 mm. The final spot size, and therefore the microscope resolution, is limited by the aberration of this lens to about 6 Å.The lens has been constructed very carefully, maintaining a tolerance of + 1 μ on all critical surfaces. The gun is prealigned on the lens to form a compact unit. The only mechanical adjustments are those which control the specimen and the tip positions. The microscope can be used in two modes. With the lens off and the gun focused on the specimen, the resolution is 250 Å over an undistorted field of view of 2 mm. With the lens on,the resolution is 20 Å or better over a field of view of 40 microns. The magnification can be accurately varied by attenuating the raster current.

Image registration with a computer driven S.T.E.M.

1978 ◽  
Vol 36 (1) ◽  
pp. 98-99
Author(s):  
A.M.H. Schepman ◽  
J.A.P. van der Voort ◽  
J.E. Mellema
Keyword(s):  
Spot Size ◽  
Scanning Transmission Electron Microscope ◽  
Small Computer ◽  
Structural Studies ◽  
Area Of Interest ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Specimen Area ◽  
On Line ◽  
Minimum Distances

A Scanning Transmission Electron Microscope (STEM) was coupled to a small computer. The system (see Fig. 1) has been built using a Philips EM400, equipped with a scanning attachment and a DEC PDP11/34 computer with 34K memory. The gun (Fig. 2) consists of a continuously renewed tip of radius 0.2 to 0.4 μm of a tungsten wire heated just below its melting point by a focussed laser beam (1). On-line operation procedures were developped aiming at the reduction of the amount of radiation of the specimen area of interest, while selecting the various imaging parameters and upon registration of the information content. Whereas the theoretical limiting spot size is 0.75 nm (2), routine resolution checks showed minimum distances in the order 1.2 to 1.5 nm between corresponding intensity maxima in successive scans. This value is sufficient for structural studies of regular biological material to test the performance of STEM over high resolution CTEM.

Ultra-spatially resolved synchrotron powered FT-IR microspectroscopy of individual cells of biological material

1995 ◽  
Vol 53 ◽  
pp. 884-885
Author(s):  
David L. Wetzel ◽  
John A. Reffner ◽  
Gwyn P. Williams
Keyword(s):  
Thermal Noise ◽  
Spot Size ◽  
Acquisition Time ◽  
Thermal Source ◽  
Signal To Noise ◽  
Spatially Resolved ◽  
Good Spatial Resolution ◽  
Small Spot ◽  
Ft Ir ◽  
Ir Microspectroscopy

Synchrotron radiation is 100 to 1000 times brighter than a thermal source such as a globar. It is not accompanied with thermal noise and it is highly directional and nondivergent. For these reasons, it is well suited for ultra-spatially resolved FT-IR microspectroscopy. In efforts to attain good spatial resolution in FT-IR microspectroscopy with a thermal source, a considerable fraction of the infrared beam focused onto the specimen is lost when projected remote apertures are used to achieve a small spot size. This is the case because of divergence in the beam from that source. Also the brightness is limited and it is necessary to compromise on the signal-to-noise or to expect a long acquisition time from coadding many scans. A synchrotron powered FT-IR Microspectrometer does not suffer from this effect. Since most of the unaperatured beam’s energy makes it through even a 12 × 12 μm aperture, that is a starting place for aperture dimension reduction.

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