Sealed-off CO Research Articles

Compact 1.1-W sealed-off waveguide CO laser

cw output of 1.1 W was attained from a compact (14-cm discharge length, 2-mm bore diameter tube) sealed-off CO waveguide laser operating in the HE11 mode. The BeO laser tube, cooled to 210 °K, was operated at the 1-W level for more than 4 h without output degradation and with a 5.7% efficiency. A mixture of CO:He:Xe:N2 in the ratio of 1:8:1:1, at a total pressure of 80 Torr, was found to be optimum, confirming the scaling or similarity rule of the product of optimum pressure and tube diameter for CO at this temperature. The output spectrum consisted of about 10 lines, between 5.20 and 5.65 μ. Laser operation without N2 (1:8:1:0) was also observed. Black particles found in the tube were x-ray identified as Ni plus NiO, indicating sputtering from the Ni cathode.

Characteristics of sealed-off waveguide CO2lasers

Gain and output power of sealed-off waveguide CO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> lasers are presented as a function of gas mixtures and total gas pressure. Experimental data on circular-bore and square-channel waveguide lasers are presented. Output power per unit length of 0.2 W/cm is achieved for both types of lasers in agreement with gas-discharge scaling laws which are presented. Saturation intensities as high as 24 kW/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> are inferred from the data. The effects of the optical properties of the waveguide wall material on the waveguide losses are discussed and theoretical waveguide loss versus wavelength is presented for BeO, Al <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> O <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> , and fused silica.

Lamb dip in CO lasers

Measurements are reported of the Lamb dip on 16 vibrational-rotational lines of low-pressure CO lasers. The experimental curves are fitted to a theory that takes into account velocity-changing collisions of the lasing molecules. The inhomogeneous and homogeneous linewidths, velocity-changing collision rate, and saturation intensities are determined for a gas mixture typical in sealed-off CO lasers.

Lamb dip in sealed-off CO lasers

Lamb dip in sealed-off CO lasers

SEALED-OFF OPERATION OF STABLE CO LASERS

Several watts of stable (Δf/f≤3×10−10) pure TEM00q-mode output power was obtained from completely sealed-off CO lasers at operating temperatures between +35 and −90°C. No deterioration of output powers has been seen after hundreds of hours of sealed-off operation.

One-year operation of sealed-off CO2laser

Continuous operation of a sealed-off CO 2 laser oscillator has been achieved over a period of one year. The power output of the oscillator at the conclusion of the test was 4.1 watts compared to its original power of 6.5 watts.

Deposits in a sealed-off CO&amp;lt;inf&amp;gt;2&amp;lt;/inf&amp;gt;laser-type discharge

In a sealed-off CO 2 laser, deposits are formed from the gas mixture. The removal of the gas in this way limits the lifetime of the laser. Fragments of these deposits are analyzed mass spectrometrically and their possible composition is given. After the discharge tube was pumped down, the gases released from the walls were analyzed. CO 2 was observed and it was apparently trapped at the walls.

Correction to "Characteristics of a single-frequency sealed-off CO2 laser amplifier"

Correction to "Characteristics of a single-frequency sealed-off CO₂ laser amplifier"

Active frequency stabilization of a 20 watt CO2laser with etalon wavelength selection

An active laser frequency stabilization scheme involving the use of an internally vibrated laser mirror has been successfully used to stabilize the output of a two-meter long, sealed-off CO 2 laser operating at powers greater than 20 watts. Long-term frequency variations in the laser were reduced from a free-running stability of about 4 parts in 107to a peak variation of 1 part in 108by this electronic technique. Heterodyne beat frequency measurements were used to obtain the data. The laser short-term stability was improved by hermetically sealing the region between the GaAs Brewster windows and the laser mirrors.

Characteristics of a single-frequency sealed-off CO2amplifier

The measured small-signal gain of 4.8 dB/m for a sealed-off COs amplifier with average bore of 25 mm compares favorably with the highest gain published for a flowing-gas type. The saturated gain for this 9-meter amplifier was 1.2 dB/m with 95-watts output when sealed off and 1.3 dB/m with 110-watts output for a flowing-gas system.

Population inversion of the vibrational levels in CO&amp;lt;inf&amp;gt;2&amp;lt;/inf&amp;gt;lasers

The vibrational level populations in CO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> lasers with mixtures of CO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> , N <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> , CO, and He have been calculated using a method developed previously in [1] and [2]. A number of transition probabilities between the vibrational levels due to molecular collisions, the dependences of the population inversion upon various laser parameters (such as the total and partial pressures of the gases, electron density, and tube radius), and the radial profile of the laser gain are calculated in this paper. The calculations show that the CO molecules formed in the discharge play a significant role in the laser. The results given in this paper and in [2] allow us to explain all the main characteristics of both the pumped and the sealed-off CO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> lasers.

20-watt single-frequency CO2laser

A short-term frequency-stabilized, single-frequency, sealed-off CO 2 laser is described which is capable of emitting 20 watts in a single mode. The technique used to obtain both high power and high frequency stability simultaneously utilizes a master oscillator-power amplifier approach. The oscillator consists of a 3-5 watt, 1-meter long Brewster angle laser. Single wavelength operation is obtained by length tuning the laser. Heterodyne measurements on two oscillator units have indicated short-term stabilities of better than 1:109(30 kHz) in a normal laboratory environment. Instabilities are primarily due to atmospheric pressure fluctuations, airborne vibrations due to laboratory noise and vibrations from the cooling water used with the lasers. Long-term frequency stabilities of about 1:107(3 MHz) have been obtained by thermal control techniques alone. The amplifier required to increase the laser power to 20 watts consists of two dc-operated 2-meter long tubes with Brewster windows. The design and operating characteristics of the laser will be given with up-to-date performance results.

The influence of xenon on sealed-off CO&amp;lt;inf&amp;gt;2&amp;lt;/inf&amp;gt;lasers

The role of xenon as a gas additive in sealed-off CO 2 -N 2 -He and CO 2 -He lasers has been investigated. Maximum Output power and maximum efficiency are increased by about 25 percent and 15 percent, respectively. The operating conditions of the lasers shift to higher currents with an accompanying 20 to 25 percent decrease in discharge voltage. An operating life of 2800 hours has been demonstrated by a sealed-off CO 2 -Xe-He-laser. Comparative measurements have been made of the electron temperature and electron density in CO 2 -N 2 - He and CO 2 -Xe-He laser discharges. With gas pressures and current adjusted for optimum laser performance, CO 2 -Xe-He discharge is characterized by a higher (∼45 percent) electron density.

A study of gas compositions, radiation output, and lifetimes of sealed-off CO2systems

A study of gas compositions, radiation output, and lifetimes of sealed-off CO₂systems

The effect of water vapour and hydrogen on the gas composition of a sealed-off CO2 laser

Abstract A mass spectrometric analysis of the gas composition of a CO 2 laser as a function of operation time is presented. It is shown that the production of CO depends on the hydrogen concentration of the gas mixture.

Continuous operation of a long-lived CO2laser tube

A sealed-off CO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> laser tube was operated with continuous, almost constant, power output at 10.6 μm for more than 1000 hours. A Ni cathode that was maintained at 300°C acted as a catalyst to regenerate CO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> back into the tube from the oxygen and carbon monoxide formed in the discharge. By the time 1100 hours of operation had passed, 92 percent of the original CO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> concentration was still available in the tube.

HIGH-OUTPUT POWERS AND LONG LIFETIMES OF SEALED-OFF CO2 LASERS

Output powers up to 63 W/m and lifetimes in excess of 1000 hr are obtained with sealed-off CO2 lasers. The addition of 0.2 torr H2O or 0.2 torr H2 to the convential mixture of CO2, N2, and He is essential for obtaining these results. The influence of the observed OH radials on the extended lifetime is discussed.