Continuous Gas Laser Research Articles

A Power Supply for a Gas-Discharge Laser Based on a Lithium–Polymer Battery

The results of experimental studies are presented and the experience of operating the power supply of a continuous gas laser, which is based on a lithium–polymer storage battery without an intermediate voltage converter, is analyzed. The long-term (more than 4-year) operation of a high-voltage battery power supply as a component of a laser system with an open-circuit voltage of 7.76 kV, a load voltage of 6.1 kV, a load current of up to 250 A, a power higher than 1.5 MVA, and a stored energy of 550 MJ is demonstrated. The response time of the switch for disconnecting the load in the case of breakdowns in the discharge chamber did not exceed 120 μs. The results of measurements of the internal resistance of the batteries and its changes during operation are presented.

Thermooptical processes in the window of a high-power gas laser

We have developed a mathematical model of thermomechanical and thermooptical processes that proceed in the output window of a continuous gas laser of a multikilowatt power. Optimal parameters have been determined at which the output window not only successfully withstands an extreme radiation load, but also ensures the radiation coupling with a minimum possible divergence. We have used numerical modeling to analyze the properties of the most promising materials used in high-power СО2, СО, and oxygen–iodine lasers.

Modeling the thermomechanical processes in the output window of a high-power СО2 laser

A mathematical model of thermomechanical processes in the output window of a high-power continuous gas laser is developed and used to examine the windows of a СО2 laser. The dependence of the maximum allowed output radiation power on the beam diameter and the distributions of temperatures and mechanical stresses are obtained, and the divergence of radiation is studied for windows made from ZnSe, KCl, and polycrystalline diamond (PD). In addition, the damage threshold of a composite output window made from PD with a single-crystalline region at the center is considered.

Raman-Microsampling Technique Applying Optical Levitation by Radiation Pressure

We report on a new Raman microprobe technique where micron-sized solid particles are trapped in stable optical potential wells using only the force of radiation pressure from a continuous gas laser. We demonstrate this technique with Raman spectra from spherical and non-spherical particles of sizes ranging between 10–30 μm. The particles are stably supported by a vertical directed focused TEM00-mode cw argon ion laser of ∼500 mW. The latter simultaneously serves as the exciting light source. Several suggestions for improvements of this technique are made.

Principle of vibrational control: Theory and applications

The principle of vibrational control is presented. This principle consists in the introduction of such vibrations (with zero mean value) of the dynamic system parameters which modify the properties of the system in a desired manner. Unlike conventional control principles, vibrational control does not require measurements of deviations and disturbances. Classes of dynamic systems are described where the vibrational control is effective for ensuring:. 1) the stability, 2) the desired properties of the transient motions, and 3) the desired properties of the dynamic system response to the external disturbance. Applications of the vibrational control are also considered which include method of alternating-gradient focusing in particle accelerators and vibrational stabilization of glow discharge in powerful continuous gas lasers. Vibrational control principle seems to be useful in cases where feedback and feedforward principles cannot be applied.

Effect of continuous gas-laser radiation on polymethyl methacrylate

The effect of continuous powerful (up to 20 W) 10.6-μ radiation on PMM is described. The relationship between crater growth and time is established. A region of softened polymer with a clearly defined boundary, an isotherm with temperature equal to the softening point, has been detected. Theoretical estimates of the propagation velocity and depth of the crater are obtained starting from the heat balance equation. The agreement with experiment is good.

Power supplies for continuous gas lasers and similar discharges

This paper considers the design and performance of power supplies that exhibit a high voltage output at light loadings, sufficient to break down a laser tube, and a much lower voltage at greater loadings, sufficient to energize the laser at its operating point. The supply is designed around a conventional power-pack that provides the lower operating voltage with series rectifier multiplier circuits of high impedance to obtain the high breakdown voltage. Single-phase, three-phase, half-wave and full-wave circuits are considered to suit a variety of laser tubes requiring operating powers from watts to kilowatts. It is shown that the behaviour of the composite power supply is completely specified by the number of multiplication stages n and the value of the characteristic current Ic. This current is defined by Ic=V0Cf where V0 is the transformer peak ac interphase voltage, C the capacity used in the multiplication circuits and f the supply frequency. The open-circuit voltage is nV0 and when loaded to currents I>or=6Ic the output voltage drops to that of the conventional power-pack with its associated ripple.

Alignment technique for the Mach-Zehnder interferometer using a laser

Iterative technique using continuous gas laser for alignment of Mach-Zehnder interferometer for monochromatic and white light fringes

Paper 12: Fog Droplet Observations in Laval Nozzles and in an Experimental Turbine

By measuring the extinction coefficient of visible light, the mean droplet size in steam fog of known dryness may be determined on the basis of light-scattering theory. A device comprising a continuous gas laser as the light source and a photomultiplier tube as the sensor is described together with experimental results obtained in low-pressure steam fogs. These were produced in Laval nozzles in one experiment, while in another experiment the fog in the exhaust casing of a model low-pressure steam turbine has been studied.

Fluorescence spectra of chlorophyll excited by a continuous gas laser

Fluorescence spectra of chlorophyll excited by a continuous gas laser

Optical simulation of microwave antennas

It has recently been suggested that microwave antennas may be simulated at optical frequencies using the neon-helium continuous gas laser. The present paper discusses various aspects of this problem and presents a simulation example using as a model the 96-element Australian array used to scan the surface of the sun at 80 megacycles. An optical system can be used for simulation in which an objective lens obtains the Fourier transform of the antenna aperture field which may be photographed. An additional lens produces an image of the antenna aperture field in the same air space as the far field pattern, thus permitting photographs of near field as well as far field patterns. Antenna masters are made as optical transparencies using photographic plates or film. Phasing may be obtained by using a variable thickness optical material evaporated on glass. Various combinations of array distribution, antenna weighting, and phasing are possible to simulate. Atmospheric perturbations are introduced on the antenna pattern by the use of two-dimensional phase delay patterns. Photographs are presented of the antenna aperture field, the far field pattern and several intermediate near field patterns.

A small and stable continuous gas laser

A small and stable continuous gas laser