Waveguide Carbon Dioxide Laser Research Articles

Analysis and Applications of Carbon Dioxide Laser

As the lasers appeared in the last century, scientist made a lot of efforts to discover the properties of them. After decades of research, lasers have become an important part in our daily life today. Lasers with different functions have been used in various fields. The purpose of writing this paper is to make readers understand the laser better. In this paper, there is an explanation of laser at the micro level. Besides, this paper also introduces the construction of RF Wave guide carbon dioxide laser, and analyzes the natures of carbon dioxide laser as well as its different applications. In the end, some recommendations and prospects of the development of the carbon dioxide laser are stated.

Theoretical and Experimental studies on CH3OH THz Laser Pumped by Pulse Carbon Dioxide Laser

In this paper, according to the molecular structure and vibration mode of micro-asymmetric gyroscope CH3OH molecule, dynamic process of optically pumped Terahertz laser is analyzed theoretically. The rate equation models based on three level systems are given according to the theory of typical laser rate equation. The output THz pulsed laser waveform is obtained by solving the rate equation model. An all-metal Terahertz laser pumped by RF waveguide carbon dioxide laser is designed with CH3OH as its working gas. The pulsed Terahertz laser output is obtained. The waveform and repetition frequency of the optically pumped laser are measured in the experiments. The Terahertz laser designed does not need water cooling system. It also has the advantages of simple structure and small size.

Surface melting of Al–Cu–Mg alloy using a short-pulse, planar waveguide CO2 laser for corrosion resistance improvement

A newly available pulse format for planar waveguide carbon dioxide lasers has been investigated for surface melting treatment of Al-2024 using 35–40 μs duration pulses. A single-pass raster scan produces crack free surfaces, but with considerable surface modulation and stress. A double-pass treatment has been shown to relieve the stress and smooth the surface, restoring the corrosion resistance of the surface to that of the parent alloy.

Precise Microanalysis of Biological Remains Using a Process of Laser Ablation

A precise analysis of the biological remains is presented in the paper. A single-channel waveguide carbon dioxide laser is used in a process of ablation ‘ for the exposing of biological remains of mineralised organisms found in a sea slime used as a component in some technological process.Many important applications of the laser base on the process of ablation. These include also so precise biomedical uses like structural studies of biomolecules. Among of the wide range of the laser devices the waveguide carbon dioxide lasers can be used in a precise biological investigations. A single-channel waveguide CO2 laser emits very easy the optical wave formed in a single, so called quasi-Gaussian, mode2. The distribution of the intensity of the laser output radiation in a basic Gaussian mode is shown in Figure 1. A high quality laser output beam in a basic Gaussian mode can be easy focused permitting a precise ablation of the investigated material in a very small area of 100 μm and less.

Enhanced peak power and short pulse operation of planar waveguide CO2 lasers

We report a large peak power enhancement and reduction in pulse width for planar waveguide carbon dioxide lasers. Gain modulation through rf discharge power switching produces trains of laser pulses with peak power levels at up to 38 times the cw power level, with a pulse duration as low as 10 μs. Operation at repetition rates in the kHz region preserves the average power (100 W) of the normal cw/long pulse mode of operation. The laser is shown to operate close to the predicted boundaries dictated by thermal loading of the discharge.

Transverse mode propagation and gain coefficients in a planar waveguide CO/sub 2/ laser amplifier

The transverse mode propagation and amplification characteristics of a large electrode area, planar waveguide carbon dioxide laser amplifier have been investigated. Amplification of an imperfectly mode-matched input produces varying output beam quality with changing discharge conditions, through the modification of the propagation constants of the waveguide modes by the gas thermal lens. For improved mode-matching to the amplifier, a near ideal TE/sub 1/ output is obtained without discharge-induced variations. The maximum gain coefficient for propagation in the fundamental mode is shown to be dependent on the radio frequency discharge conditions through the frequency dependence of the minimum stable power density. At 81 MHz, a gain coefficient of 0.65 m/sup -1/ at 50 torr pressure is obtained.

Direct measurement of the electrical impedance of narrow gap radio frequency gas discharges in the 100 MHz region

A discharge cell is described in which direct measurements of the inter-electrode voltage, current density and phase angle of narrow gap RF gas discharges are possible, with good accuracy in the 50 to 200 MHz region. Examples are given of the use of the arrangement to determine the electrical impedance of discharges in slab waveguide carbon dioxide lasers.

Propagation characteristics of coherent array beams from carbon dioxide waveguide lasers

The characteristics of coherent array beams generated by waveguide carbon dioxide laser structures have been investigated, with particular emphasis on their propagation and transformation properties. Methods of array beam generation are presented, and measurements of array beam quality are given through the use of the M/sup 2/ parameter. Efficient transformation of an array beam from the antisymmetric to symmetric pattern is achieved through the use of a binary phase plate, and spatial filtering is shown to improve the beam quality at the expense of only a moderate loss of total beam power. Coherence effects in the near-field propagation of array beams are also explored.

High-power two-dimensional waveguide CO/sub 2/ laser arrays

A two-dimensional, 39 element array of waveguide carbon dioxide lasers has produced a total CW laser power output of 750 W, using RF excitation of a compact, close packed assembly. Thermal effects associated with close-packing in the array are evaluated in terms of discharge wall temperature rise and cavity mirror distortion. The array elements are shown to have a 30% power derating relative to a single isolated laser channel, caused mainly by internal temperature rise. Mirror distortion and waveguide constructional errors do not degrade the beam quality of the array emission, which matches the theoretical value. However mirror distortion is shown to be responsible for a large spread in laser frequency between channels in the array. Based on the results, prospects are good for the construction of larger, multikilowatt incoherent arrays.

Waveguide CO2Lasers: Frequency Stability, Frequency Locking and Measurements of Dipole Moments ofv6andv8Vibrational States in Formic Acid

Abstract A waveguide carbon dioxide laser is stabilised on the Lamb-dip of a Stark-tuned molecular absorption and offset locked. Further an acousto-optic modulator is used to produce a single sideband of the CO2 laser. The infrared-infrared double-resonance signal in formic acid is observed and dipole moments of v 6 and v 8 vibrational states are determined.

Spatial distributions of translational and vibrational temperatures of molecules in a waveguide CO2laser plasma

Methods developed for diagnostics of the active media of waveguide carbon dioxide lasers at elevated pressures and input energies in a capillary gas discharge were used to study the mechanism of gas heating and pumping of vibrational levels in a CO2–N2–He (1:1:8) mixture. As a result of spectroscopic experiments with an actual spatial resolution of ~0.2 mm, radial distributions of the translational and vibrational temperatures of the molecules were reconstructed as a function of changes in the discharge conditions. The results could be used to establish the mechanism of gas heating in a capillary discharge of a waveguide CO2 laser.

Influence of xenon on sealed-off operation of rf-excited CO2 waveguide lasers

The addition of xenon to helium, nitrogen CO2 gas mixtures is shown to increase output power by 24% in sealed-off rf excited waveguide carbon dioxide lasers. Experiments with a range of laser output couplers indicate that this improvement is due to a corresponding increase in small signal gain, with the saturation intensity remaining fairly constant.

Discharge striations in rf excited waveguide lasers

The existence of transverse striations in radio-frequency discharge excited waveguide carbon dioxide lasers is reported. A simple model indicates how these effects can be explained in terms of internal space-charge fields. An additional effect of the space-charge regions on the discharge capacitance is described.

A 10 W single mode Pyrex waveguide CO2laser

Describes a Pyrex waveguide carbon dioxide laser operating at a maximum single line power of about 10 W. Although construction is straightforward, excellent single mode purity is achieved in a far simpler way than most conventional systems.

A frequency-stabilised CW waveguide carbon dioxide laser

The operation and performance characteristics of a frequency stabilised carbon dioxide waveguide laser which has been designed to provide a compact, rugged and stable source of infrared radiation suitable for the non-laboratory environment is described. The laser produces a maximum output power of 4.75 W in the EH11 waveguide mode and is actively stabilised on the P(20) rotational-vibrational transition by means of an extra-cavity frequency reference provided by a Stark-effect-tunable resonance absorption in singly deuterated ammonia. Short-term (1 ms) stability of the output is about 5 kHz, and in the long term, the laser can be held to within 1 MHz for periods of many hours at a frequency which itself is voltage controllable over a range of about 200 MHz.

A compact sealed waveguide CO2 laser

The design, construction and preliminary performance data are reported for a compact waveguide carbon dioxide laser which produces a high output power per unit length. The laser of overall length 15 cm produces 3.85 W from only 9.4 cm of discharge. This figure corresponds to an output power per unit length of 410 mW cm-1, which is a factor of two higher than previously reported measurements. It is shown that this value is consistent with theoretical predictions based on the gain and saturation intensity measurements in the literature.