The Effect of the Instability of the Sensitivity of a Matrix Receiver to the Measurement Error of the Space-Energy Characteristics of a Laser Beam

2019 ◽  
Vol 61 (10) ◽  
pp. 996-1000
Author(s):  
A. M. Raitsin ◽  
M. V. Ulanovskii
Keyword(s):  
Measurement Error ◽  
Laser Beam ◽  
Energy Characteristics

Research of On-Line Large-Size Forging Measurement System Based on LabVIEW

2012 ◽  
Vol 430-432 ◽  
pp. 1577-1580
Author(s):  
Xian Ling Zhao ◽  
Jian Sheng Liu
Keyword(s):  
Measurement Error ◽  
Laser Beam ◽  
Measurement Errors ◽  
Three Dimensional ◽  
Automatic Measurement ◽  
Manual Measurement ◽  
Large Size ◽  
On Line ◽  
Large Measurement ◽  
Time Changes

Forging temperature is usually around 1000°C in free forging scene. Manual measurement leads to large measurement errors. Adopting the non-contact 3D scanning technology, make the laser beam sweep across the forging surface to get three-dimensional coordinates of the points on the forging surface in space. Neighboring scan points separate by less than 0.25mm. The measurement error is less than 6mm. The coordinate,s data are sent to the LabVIEW procedure. The procedure analyzes the coordinates to calculate the size of the large-size forging to realize automatic measurement of the forgings. The procedure can also reconstruct the image of the large-size forging. These make us detect the real-time changes of the forging far from the free forging scene.

Effects of Key Parameters on the Performance of a New In-Process Optical Measurement Method

2005 ◽  
Vol 295-296 ◽  
pp. 405-410 ◽  
Author(s):  
Z. Tao ◽  
Y. Gao
Keyword(s):  
Measurement Error ◽  
Theoretical Analysis ◽  
Laser Beam ◽  
Measurement Method ◽  
Optical Measurement ◽  
New Method ◽  
Acceptable Range ◽  
Measuring Surface ◽  
Surface Profiles ◽  
Optical Measurement Method

A new in-process optical measurement method has been developed for measuring surface profiles of workpieces under the coolant condition. In this method, a laser beam passes through two additional layers. This paper presents an error analysis for the new method. The effects of key parameters on performance of the new method are examined. The theoretical analysis and experimental results show that the measurement error in this new method can be controlled within an acceptable range.

Correct measurement methodology spatial-energy characteristics of laser beams

Metrologiya ◽  
2021 ◽  
pp. 4-19
Author(s):  
A. M. Raitsmm ◽  
M. V. Ulanovskii
Keyword(s):  
Laser Beam ◽  
Dynamic Range ◽  
Radiation Detectors ◽  
Test Methods ◽  
National Standard ◽  
Laser Beams ◽  
Energy Characteristics ◽  
Uniformity Of Measurements ◽  
Spatial Intensity Distribution ◽  
Array Detectors

A methodology for correct measurements of the spatial and energy characteristics of a laser beam is considered, based on the determination of the initial moments of the spatial intensity distribution in the beam cross section. The classification of radiation fields participating in the measuring process is given: emitted, measured and measured. It is shown that ISO 11146:2005 “Lasers and laser-related equipment. Test methods for laser beam widths, divergence angles and beam propagation ratios, Part 1-3” for measuring the spatial and energy characteristics of laser beams leads to incorrect measurements. This is due to the fact that the recommendations for the application of ISO 11146:2005 do not take into account the dynamic range of the used matrix radiation detectors, and the characteristics of the emitted field of interest to the user turn out to be diverging, which violates the uniformity of measurements. Moreover, the conditions ensuring the convergence of the results are practically impracticable. To solve these problems, it is proposed to establish and regulate the lower level of the dynamic range of measurements of the intensity of the used matrix receivers and to consider the spatial and energy characteristics of the emitted field of interest to the user, depending on the set value of the lower level. It is shown that measurements with this methodology become correct and make it possible to compare the characteristics of laser beams obtained by different array detectors. Formulas are given that take into account the effect of the lower level of the dynamic range of the matrix radiation detectors on the measurement result. These formulas should be recommended for inclusion in the updated edition of the national standard GOST R ISO 11146-2008 “Lasers and laser installations (systems). Methods for measuring widths, divergence angles and propagation coefficients of laser beams. Parts 1-3”.

Two-photon excitation microscopy in cellular biophysics

1995 ◽  
Vol 53 ◽  
pp. 62-63
Author(s):  
David W. Piston ◽  
Brian D. Bennett ◽  
Robert G. Summers
Keyword(s):  
Confocal Microscopy ◽  
Laser Beam ◽  
Duty Cycle ◽  
Excited Electronic State ◽  
Input Power ◽  
Two Photon ◽  
Simultaneous Absorption ◽  
Photon Excitation ◽  
Very High ◽  
Two Photon Excitation

Two-photon excitation microscopy (TPEM) provides attractive advantages over confocal microscopy for three-dimensionally resolved fluorescence imaging and photochemistry. Two-photon excitation arises from the simultaneous absorption of two photons in a single quantitized event whose probability is proportional to the square of the instantaneous intensity. For example, two red photons can cause the transition to an excited electronic state normally reached by absorption in the ultraviolet. In practice, two-photon excitation is made possible by the very high local instantaneous intensity provided by a combination of diffraction-limited focusing of a single laser beam in the microscope and the temporal concentration of 100 femtosecond pulses generated by a mode-locked laser. Resultant peak excitation intensities are 106 times greater than the CW intensities used in confocal microscopy, but the pulse duty cycle of 10-5 maintains the average input power on the order of 10 mW, only slightly greater than the power normally used in confocal microscopy.

The atomic-force microscope and its future in biology

1993 ◽  
Vol 51 ◽  
pp. 704-705
Author(s):  
Jean-Paul Revel
Keyword(s):  
Silicon Nitride ◽  
Laser Beam ◽  
Atomic Force Microscope ◽  
Scanning Tunneling Microscope ◽  
Point Of View ◽  
Scanning Tunneling ◽  
Close Relative ◽  
Tunneling Microscope ◽  
Atomic Force ◽  
Sharp Point

The last few years have been marked by a series of remarkable developments in microscopy. Perhaps the most amazing of these is the growth of microscopies which use devices where the place of the lens has been taken by probes, which record information about the sample and display it in a spatial from the point of view of the context. From the point of view of the biologist one of the most promising of these microscopies without lenses is the scanned force microscope, aka atomic force microscope.This instrument was invented by Binnig, Quate and Gerber and is a close relative of the scanning tunneling microscope. Today's AFMs consist of a cantilever which bears a sharp point at its end. Often this is a silicon nitride pyramid, but there are many variations, the object of which is to make the tip sharper. A laser beam is directed at the back of the cantilever and is reflected into a split, or quadrant photodiode.

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