The paper presents the experimental and theoretical evaluation of sensitivity of the copper bromide vapor brightness amplifier (l=50 cm; d=3.2 cm). The research was performed in two experimental modes: Single-Pass brightness amplifier system and the Master oscillator Power Amplifier (MOPA) system. The dependencies of the gain factor (K) and the output signal power (POUT) on the input signal power (PIN) are shown. The input signal power was wearied from 2 μW to 200 mW. The results show that the minimal input signal power, which can be amplified, is (0.001÷0.010) % of ASE power.
We present the amplifying features of the copper bromide brightness amplifier excited by a capacitively coupled longitudinal discharge. The dependences of the amplified spontaneous emission (ASE) power, gain, and the sensitivity of the brightness amplifier on the pulse repetition frequency (PRF) of the excitation have been obtained. The PRF of excitation varied from 12 to 24 kHz. At PRF 24 kHz, the output power was 2.1 W, pulse duration was 30 ns that is lower than for a copper bromide brightness amplifier with the typical excitation pulses. The small-signal gain reaches 0.25 cm − 1, which is commensurate for a copper atom active media with the typical excitation charge. The sensitivity of the investigated amplifier is 0.01% of ASE power in the studied PRF range.
The use of metal atom active media allows to convert optical signals with the transferring of the adjusted contrast. Due to the opportunities of metal vapor active media it makes possible to increase the intensity of the signal in the narrow spectral range. As a result, the signal-to-noise ratio can be dramatically increased. It makes possible to build active optical systems for high speed imaging of processes which are hidden by high intensive radiation. In the systems is available the image active filtration due to induced transition on metal atoms. Active optical systems with metal vapor brightness amplifiers (which is called Laser monitor), have shown the high efficiency for reducing the background radiation effect on the observing processes in the real-time mode. Moreover, the use of different active media makes it possible to change the spectral contest of the input signal with the increasing of the intensity. In the work the result of the research such systems are presented. The method of transformation IR images to VIS images is discussed. The work presents the results of the using of different active optical systems for high speed imaging.
To optimize the welding processes and quality of a fixed connection needs to study of the melting and transfer of electrode metal into the weld pool. The paper discusses the results of studies of high speed processes of heat and mass transfer during arc welding with consumable electrodes. The imaging of such processes is difficult due to the presence of powerful light radiation from a welding arc. Its glow makes it practically impossible to obtain a satisfactory image using “simple” high-speed video recording methods. Our experimental researching has shown that the most effective method to improve the image quality of the studied object is the laser imaging method. It allows to significantly reduce the negative effects of background radiation. In the course of the research, the opportunity of using the CuBr laser with the narrow-band filters to image the observed object was shown.
The intensive development of beam, plasma, discharge and laser technologies makes non-destructive testing methods and devices based on passive and active optical systems. There is an active optical system, which is called a laser monitor. The using of this system makes it possible to form images of test objects and processes suitable for analysis even under background radiation, however, the imaging distance does not exceed 3.3 m. The bistatic scheme of the laser monitor is designed to expand the capabilities of imaging using active media on metal vapors. This paper shows the operation features of the bistatic laser monitor as well as the parameters of the formed images. One of the issue is to compare the amplification of image brightness in an optical converter due to the different laser monitor scheme modification.
The paper presents the results of study some dynamic characteristics of the copper brightness amplifier. The active medium of the copper vapor laser was used as a brightness amplifier. The time dependence of the gain is considered. Optimal time delays between the reflected signal and the amplified are presented. The results of the study can be used for the developing of visualization systems by means of such image brightness amplifiers.
The control system for bistatic laser monitor was developed. This system includes digital circuit and high-voltage modulator. The control system provides synchronous pumping of two active elements: an illumination source and a brightness amplifier. The time shift between triggering pulses is regulated by a variometer and its maximum value is 40 ns in case active load. The MOPA system was realized. Experiments on visualization of a test object were done. The example of such visualization was demonstrated.
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