Method of Reducing the Error of Transferring the Size of a Unit of Laser Radiation Energy

A method is considered of reducing the error of transferring the size of a unit of laser radiation energy for a secondary standard of the units of average power and energy of laser radiation by using the readings of a relative-level sensor. A procedure is developed for processing the readings of this sensor.     

Consideration of the Effect of Instability of the Laser Emission Power on the Final Result of the Reproduction of the Unit of Mean Laser Emission Power and the Transmission of Its Dimensions

An algorithm for reconstructing the form of continuous laser emission at the input of a system for measuring the standard of the unit of mean laser power is presented. The power can also be calculated using this algorithm.     

Computer Modeling of an Optical Radiometer

The problem is considered of creating a uniform structure for the various categories of a standard for the unit of average laser radiation power. The approach is based on directly synthesizing the structure of a standard instrument. As an example, a computer modeling is carried out of a combination which is typical for many types of measurement, namely a measurement transducer and a voltmeter, and this was applied to the case of measuring average laser radiation power.     

The state primary standard for the unit of mean laser power

An upgraded state primary standard is considered for the unit of mean laser radiation power. The technical characteristics and working principle are given. __________ Translated from Izmeritel’naya Tekhnika, No. 7, pp. 3–6, July, 2007.     

Assurance of the Uniformity of Measurements of the Power of Laser Radiation

On the basis of an analysis of the principle underlying the construction of standards and systems designed for reproduction of the unit of mean power and energy of laser radiation, it is shown that these standards consist of unified subsystems that carry the principal metrological load. By means of such a division, it is possible to realize a systems-engineering synthesis of standards with preassigned error. __________ Translated from Izmeritel'naya Tekhnika, No. 11, pp. 20–23, November, 2005.     

Mathematical Simulation of Radiation Instability and a Possible Method of Taking Instability into Account in Realization of the Unit of Power of Laser Radiation and Dissemination of the Unit of Power

The present study is devoted to mathematical simulation of the instability of laser radiation. An algorithm for establishing the shape of continuous laser radiation received at the input of a measuring system is presented.     

Measurement Transducer – Digital Voltmeter System for Measuring the Energy of Laser Pulses

The results are given of theoretical investigations and of a simulation modeling of the process of measuring the energy of short-pulse laser radiation. The grounds are given for choosing the principal parameters of the measurement transducers depending on the probability density distribution function of the values of the output signal. Comparative values are given of the relative standard deviation in accordance with a proposed mathematical model and with experimental data obtained using a working standard of the unit of energy created at the All-Russia Scientific-Research Institute of Optophysical Measurements.     

A Method of Transferring the Unit of Power of High-Intensity Laser Radiation

Measurement Techniques - A method is proposed for transferring the unit of mean power of laser radiation by means of measuring high-intensity power (kilowatts), with the possibility of constant...     

Continuous chemical HF laser with a modified radially expanding nozzle unit

We have determined experimentally the energy and spectral characteristics of a supersonic continuous chemical HF laser (oscillator) with a modified radially expanding nozzle unit operating according to the “nozzle–injector–injector” scheme of mixing reactants based on a new method of obtaining oxidizing gas. The practical realization of measures to decrease the heat loss and the loss of fluorine atoms, as well as the optimization of the mode of operation of the modified laser, permitted a 30% increase in its radiation power compared to the base oscillator equipped with a nozzle unit operating according to the “nozzle–injector” mixing scheme. Ways of further enhancement of the energy characteristics of the HF laser radiation are proposed.     

Method of Extending the Dynamic Range of the Secondary Standard of the Units of Mean Power and Energy of Laser Radiation

A method of extending the dynamic range of the secondary standard of the units of the mean power and energy of laser radiation into the low-level region is considered. A technique of calculating the optimal transmission coefficients for a set of attenuators is developed.     

A theoretical study of the metrological characteristics of a calibrated fresnel attenuator of the beam power of laser radiation

A theoretical investigation of the metrological characteristics of a precision Fresnel attenuator is performed for the purpose of determining whether it can be employed as a comparison standard intended for comparing the domestic primary standard of the unit of mean power of continuous laser radiation with an absolute cryogenic radiometer.     

Non-Selective Standard Indicator for the Average Power of Laser Radiation

A technical solution for the average power laser radiation standard applied to the ultraviolet range is suggested and characteristics of the standard are provided.__________Translated from Izmeritelnaya Tekhnika, No. 2, pp. 32–35, February, 2005.     

A novel small‐hole blockage detection laser module in the LC connector on‐line inspection

Abstract

A small‐hole blockage detection module using a 655 nm wavelength laser is developed to improve production yield and to guarantee the ferrule assembly's quality. This module includes a spot size contractor, a laser emitter/receiver unit, and a ‘roller gear cam index’ based automatic machine. The optical path blockage within a ferrule entry or ferrule hole is totally determined by the amount of laser power detected by the receiver unit. Experimental work was carried out based on both clean and defective ferrule assemblies. The four‐position average method provides a reliable detection algorithm in the experiment. The theoretical derivation of the laser beam contraction and experimental set up of the detection process are presented in this study.     

Restrictions in implementation of multistage laser amplifiers

The results of a simultaneous account of the influence of the amplifying properties of an active medium of a laser amplifier and its inhomogeneities on energy characteristics in an application zone are given. An intensity is described to the approximation of linear and saturated gain. Distortions in the active medium are accounted for by the wave front dispersion. A simultaneous account of inverse indices and optical quality has allowed determination of an optimal number of amplifying stages of a laser unit providing the maximum radiation power density in the application zone.Institute of Mechanics, St. Petersburg, Russia. Translated from Inzhenerno-fizicheskii Zhurnal, Vol. 64, No. 1, pp. 63–66, January, 1993.     

Effect of laser induced rapid solidification structures on adhesion and bonding characteristics of alumina/silica based oxide to vitreous enamel

Abstract

The present work is concerned with investigating the effects of high power diode laser (HPDL) radiation on the microstructure of an amalgamated alumina/silica based oxide compound (AOC). The main rapid solidification theories, namely constitutional supercooling and the theory of morphological stability, are used to explain the observed microstructural changes in the AOC resulting from HPDL interaction. Without laser treatment of the AOC surface it was impossible to fire the enamel onto the AOC. However, wetting experiments, using a number of control liquids and the sessile drop technique, revealed that laser treatment of the AOC surface significantly altered the wetting characteristics of the AOC and allowed the enamel to bond to the AOC. Accordingly, HPDL treatment was identified as allowing the vitreous enamel to wet the surface by causing a decrease in the enamel contact angle from 118° to 33°. Moreover, no discernible difference was seen in the change in contact angle across the range of rapid solidification microstructures obtained. The actual incidence of rapid surface resolidification, and not the degree of rapid surface resolidification, was therefore identified as being the primary factor governing changes in contact angle. The bonding mechanisms were identified as being principally owing to van der Waals forces, however, some evidence of chemical bonding was also observed. The work has clearly shown that laser radiation can be used to alter the wetting characteristics of the AOC.     

Theory of cutting materials with a laser beam

In strict three-dimensional statement the article investigates the steady and nonsteady problems of the shape and depth of cut originating on the surface of material under the effect of a powerful laser beam in dependence on the speed of the specimen, the direction of the beam, the power and polarization of the radiation. The known local approximation is used where the energy of destruction of unit volume is taken to be constant. The theoretical results are compared with known experimental data.Translated from Problemy Prochnosti, No. 2, pp. 56–62, February, 1991.     

Application of Laserstar Power Meter for Determination of the Stability of Laser Radiation Power

The potential for the use of the Laserstar power meter for the determination of the stability of laser radiation power is considered. A relation is established between the discreteness of the reader and the resolution in the determination of the stability of laser power. Examples illustrating the determination of the stability of the radiating power of certain lasers are presented.     

Characterization of the backscattered radiation from petawatt laser matter interactions

The development of high peak power and energy laser systems require the assurance that any backscattered radiation will not lead to damage of the laser system. We present the characterization of the backscattered radiation for different target types and conditions at petawatt power levels and intensities (>10(20)W/cm2). We observe that radiation is generated between 700 and 900 nm, as well as the expected self emission and laser fundamental. The percentage of the incident light backscattered reduces as a function of the incident energy and is typically <1% for petawatt laser interactions.     

Optico-acoustic characterization of the fractal structure of radiation from a laser with unstable resonator

The thermooptical excitation of sound in a liquid by fluctuating laser radiation with sine-modulated intensity is studied theoretically. The intensity is randomly distributed over the beam cross section. It is assumed that the random processes are homogeneous and that the spatial spectrum of intensity fluctuations obeys a power fractal law. Possibilities for the optico-acoustic characterization of the fractal radiation structure of a laser with unstable resonator are discussed.