Design of an adjustable spot size laser cladding optical system

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.

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Real-time laser cladding control with variable spot size

10.1117/12.2040058 ◽

2014 ◽

Cited By ~ 2

Author(s):

J. L. Arias ◽

M. A. Montealegre ◽

F. Vidal ◽

J. Rodríguez ◽

S. Mann ◽

...

Keyword(s):

Real Time ◽

Laser Cladding ◽

Spot Size

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Properties of Curved Parts Laser Cladding Based on Controlling Spot Size

Applied Sciences ◽

10.3390/app10020728 ◽

2020 ◽

Vol 10 (2) ◽

pp. 728 ◽

Cited By ~ 1

Author(s):

Haibo Huang ◽

Wenlei Sun ◽

Yong Huang ◽

Jiangtong Yu

Keyword(s):

Wear Resistance ◽

Laser Cladding ◽

Coating Thickness ◽

Flaw Detection ◽

Spot Size ◽

Laser Spot ◽

Reconstruction Method ◽

Laser Head ◽

Spline Surface ◽

Curvature Sphere

In this study, a method based on controlling the laser spot size was proposed in the process of curved parts laser cladding, and the coatings obtained by this method were analysed through investigation of the microstructure, microhardness, adhesion property and wear resistance properties. The nonuniform rational B-spline surface (NURBS) reconstruction method was used to obtain the workpiece geometrical characteristics of laser cladding, and through the establishment of a mathematical model, the process of the laser beam working on the curved surface was simplified as the intersection of the cylinder and curvature sphere. Then, the spot size was transformed into the area of a cylinder intersecting with a sphere, and by adjusting the laser head, the size of the laser spot was controlled in the threshold and interpolation points were obtained. The laser cladding trajectory was ensured by these interpolation points, and the experiment was carried out to study the properties of the coating. The results showed that the average coating thickness was about 1.07 mm, and the fluctuation of coating thickness did not exceed 0.05 mm; also, there were no cracks or pores in the layer after penetrant flaw detection. The SEM showed that the grains passed through the transition of plane crystal, cellular crystal, dendrite and equiaxed crystal from the bottom to the top of the layer. After 30 cycles of thermal shock tests, the cladding layer was still well bonded with the substrate and the microhardness and wear resistance were 2 times and 1.4 times higher than that of substrate, respectively.

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

International Ophthalmology ◽

10.1007/bf00137496 ◽

1979 ◽

Vol 1 (3) ◽

pp. 175-178 ◽

Cited By ~ 11

Author(s):

R. Birngruber ◽

E. Drechsel ◽

F. Hillenkamp ◽

V. -P. Gabel

Keyword(s):

Optical System ◽

Spot Size

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

Journal of Innovative Optical Health Sciences ◽

10.1142/s1793545820500182 ◽

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.

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

Journal of Synchrotron Radiation ◽

10.1107/s1600577515007742 ◽

2015 ◽

Vol 22 (4) ◽

pp. 867-878 ◽

Cited By ~ 56

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.

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

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100076159 ◽

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.

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A Field Emission System For Transmission Electron Microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100071934 ◽

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).

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