Brightness Amplifier Research Articles

Kinetics of the Active Medium of a Copper Vapor Brightness Amplifier

A spatiotemporal kinetics of the active medium of a copper vapor brightness amplifier is described that allows gain characteristics to be investigated during the pump pulse. Model calculations show that changing the discharge parameters allows the radial gain profiles to be improved significantly, as well as the gain and the inversion duration to be increased. The data obtained will be used to choose the operating conditions for the active medium in the brightness amplifier mode.

Усилитель яркости на переходах атома марганца с частотой следования импульсов до 100 kHz

AbstractResults of the development and study of an image brightness amplifier on manganese atom transitions for problems of object visualization in active optical systems are presented. The possibility in principle of using the developed active element for visualization of objects and processes in two spectral ranges—visible and near-IR—is shown. Profiles of the active element radiation beam at pulse repetition frequencies of up to 100 kHz have been obtained.

An image-brightness amplifier based on copper bromide vapor for operation at increased superradiance pulse duration

We present data on the development and application of an image-brightness amplifier based on copper bromide vapor intended for the visualization of objects occurring at distances above 5 m from the detecting equipment. An increase in the superradiance (gain) pulse duration was achieved by decreasing the repetition frequency of pumping pulses (to 3 kHz) and increasing the capacitance of the capacitor bank (up to 3.4 nF) so as to increase the deposited pulse energy. The basic possibility of creating active optical systems with brightness amplifiers (laser monitors) for the visualization of objects and processes occurring at large distances from a registration system is demonstrated.

Laser monitors for high speed imaging of materials modification and production

The methods for real-time visual diagnostics of high-speed processes of materials modification and production are presented. The main problem of visualization of such processes is the intense glare which blocks the investigated area. To decrease the negative effect of the glare (high intensive background light) the copper bromide vapor brightness amplifier is used. It has been shown that the imaging method with a brightness amplifier proposed in this paper proves to be the most reliable to obtain the information about objects or processes in a real time mode using high frequency copper bromide vapor brightness amplifier. The results of visualization of different processes, including nanoparticles production, are presented. The benefits and limitations of both methods used for imaging have been also demonstrated.

Erratum to: Spatial–temporal gain distribution of a CuBr vapor brightness amplifier

Erratum to: Spatial–temporal gain distribution of a CuBr vapor brightness amplifier

High-speed CuBr brightness amplifier beam profile

This paper addresses the experimental study of the beam profile of the CuBr brightness amplifier operating at a wide range of pulse repetition frequencies. The use of a medium-size gas discharge tube (2cm) ensures the operation of the brightness amplifier both at typical PRFs (520kHz) and at higher PRFs (up to 100kHz), either with or without HBr additive. The effect of the active additive on the beam profile is demonstrated. The testing results on kinetic modeling of radial processes in the laser (brightness amplifier) plasma are also discussed.

Laser Monitors for High Speed Imaging of Plasma, Beam and Discharge Processes

The imaging results of different processes blocked from the observation by the intense background light are presented in this paper. Active optical systems based on high-frequency brightness amplifier are used to decrease the negative factor of the glare. The experimental and modeling results on obtaining high pulse repetition frequencies (PRF) (more than 100 kHz) of copper bromide vapor brightness amplifiers operating in a low input energy mode are shown. The use of metal vapor brightness amplifiers for visual non-destructive testing of fast processes obscured by the glare is also discussed. It has been shown that the imaging method proposed in this paper proves to be the most reliable to obtain the information about objects or processes in a real time mode using high PRF CuBr active media.

A bistatic laser monitor

A prototype of a bistatic laser projection system employing copper bromide vapor based active media is presented that allows remote objects and high-speed processes to be monitored online. The proposed scheme employs two active elements: one in the source for lighting the object and another in the image brightness amplifier.

Copper bromide vapor brightness amplifiers with 100 kHz pulse repetition frequency

The paper presents a laser monitor with 10μs time-resolution based on a high-frequency copper bromide vapor brightness amplifier. A sync circuit has been designed for single-pulse imaging. The analysis of amplifying characteristics of the active elements and active optical system (laser monitor) parameters allowed to determine the optimal concentration of HBr at which the images can be obtained with minimum distortions. For the active element operating at high frequencies (more than 50kHz) as a brightness amplifier, the concentration of HBr must be lower than that needed for obtaining the maximum output power. The limiting brightness temperature of the background radiation which does not affect the image quality is determined. The potential feasibility of using a proposed brightness amplifier for visualizing processes blocked from viewing by the background radiation with the brightness temperature up to 8000K is demonstrated.

A mirror based scheme of a laser projection microscope

The paper discusses the design of a laser projection microscope with a mirror-based scheme of image formation. It is shown that the laser projection microscope with the mirror-based scheme of image formation is well suited for distant objects monitoring. This scheme allowed obtaining a field of view of more than 3 cm at the distance of 4 m from the brightness amplifier

Radial distribution of radiation in a CuBr vapor brightness amplifier used in laser monitors

The paper presents a study of the effect of excitation conditions in a CuBr vapor brightness amplifier in a monostatic laser monitor on the radial non-uniformity of the radiation bearing the information about the object being visualized. A significant dependence of radial signal distribution on the concentrations of CuBr, HBr and pumping power has been demonstrated. In particular, an increase in CuBr vapor concentration causes the gain profile of the active medium to constrict and the axial gain to increase. The conditions for the most uniform radial distribution of the laser monitor signal are substantially different from those for the maximum radiated power. The paper demonstrates HBr doping to be usable as a tool to correct the non-uniformity of the radial distribution of laser monitor radiation. An addition of ~0.15 Torr HBr broadens and flattens the radiation profile, improving an important aspect of laser monitor image quality.

High Prf Metal Vapor Laser Active Media For Visual And Optical Monitoring

In this paper the feasibility of using metal vapor lasers for visual and optical monitoring of fast processes is discussed. The theoretical calculations consistent with the experimental study have been performed. The possibility of visualizing objects with pulse repetition frequency of the brightness amplifier up to 60 kHz has been demonstrated. The visualization results of the corona discharge are also given.

Визуализация объектов, расположенных на удалении до 5 м от CuBr-усилителя яркости, с импульсом излучения типичной длительности

Визуализация объектов, расположенных на удалении до 5 м от CuBr-усилителя яркости, с импульсом излучения типичной длительности

MnBr vapor active medium with a built-in reactor at 100-kHz pulse repetition frequency

Frequency and energy characteristics of a MnBr vapor laser with a built-in reactor, i.e., with gas vapors being produced within a gas discharge tube, and the dependence of the average output power on different parameters are studied in this work. The values of the GDT wall temperature and buffer gas pressure required for obtaining the maximum output power are determined. It is shown that active media of this kind are as good as media with a conventional method of gas vapor production. A pulse repetition frequency of 100 kHz is attained for the first time for a medium on Mn atom transitions. The use of this active medium as a brightness amplifier in active optical systems is described; the amplifying characteristics are analyzed.

Observation of objects under intense plasma background illumination

Experiments on the observation of a brightness-amplified image of an object through a masking arc discharge are presented. The copper-vapor laser active medium was used as an image brightness amplifier. It is shown that the image quality does not worsen under plasma background illumination.

Visualization of plasma-induced processes by a projection system with a Cu-laser-based brightness amplifier

A novel method for visualization of the process of interaction of high-power energy fluxes with various surfaces is proposed. The possibility of the dynamic visualization of a surface covered with a ∼3-cm-thick plasma layer with a linear density of ∼1016 cm−2 is demonstrated experimentally. A scheme of intracavity shadowgraphy of phase objects with the use of a laser projection microscope is developed. Shadow images illustrating the development of the plasma torch of an erosion capillary discharge in air are presented.

Preheating of a target by laser radiation through plasma and polymer aerogel

Processing of X-ray and optical streak-camera images after brightness amplification 5 proves unambiguously the existence of a preheating of the foil in two-layer targets (polymer aerogel plus Al foil). We observed this effect earlier at the accuracy limit of the experiment. Preheating may be explained by the initial transmission of laser radiation by an inhomogeneous plasma and aerogel remnants. The fraction of laser energy that passed through a microheterogeneous plasma to the foil or shell is small in comparison with the total energy in the pulse, but it comes to the target (foil or shell) at the initial period of the laser pulse and can be significantly affected by the dynamics of plasma and the efficiency of spherical cryogenic thermonuclear targets.

Analysis of the Q2237+0305 light-curve variability with regularization technique

The microlensing high‐amplification events in the light curves of the gravitationally lensed quasar Q2237+0305 observed by the OGLE group and GLITP collaboration are analysed. The significant brightness amplification in the A and C components in 1999 observational season are considered under the assumption of the fold caustic crossing. Under this assumption we applied the model‐independent method based on regularization technique for one‐dimensional profile restoration of the quasar accretion disc brightness distribution. The recovered brightness distribution of the source seems to obey the standard model for the accretion disc. The estimated effective radius of the quasar emitting region is in agreement with the previous studies.

The use of percutaneous autologous bone marrow transplantation in nonunion and avascular necrosis of bone

During the development of normal bone in the young child, osteoblasts and then haematopoietic stem cells progressively colonise the cartilaginous matrix, resulting in its ossification to bone matrix.[1][1] It is at this time that red bone marrow appears in the skeleton, starting distally in the foot

SCOPIX: A new X-ray imaging system for core analysis

SCOPIX is a new digital X-ray imaging system for core analysis that uses an X-ray source coupled to a high-energy brightness amplifier and a CCD camera. SCOPIX’s numerical files are images in 256 gray levels equal in value to X-ray densities. Possible data processing approaches include: core logging using grayscale profiles to define the characteristics of sedimentary sequences and image processing to define and quantify lithologic facies and the geometry of physical and biological structures. Applications are: recognition of facies and sedimentary processes, study of sedimentary rhythms and geological cycles, and study of biological and geochemical processes.