History

Since the beginning:

1970: A cataphoretic He-Cd laser (our first metal vapour laser) was put into operation (following the results of J. P. Goldsborough).
1972: A copper vapour laser (CVL) with external heating was put into operation (following the results of W. T. Walter).
1974: A copper bromide vapour laser (CuBrVL), a low temperature version of the CVL, was put into operation for the first time in the world. A little later the first CuBr laser, a low temperature version of the copper self-terminating laser, was developed and put into operation (Bulgarian patent No.:28674). Read more
1982: The helical hollow cathode was developed for use in metal vapour ion lasers (M. Grozeva and N. Sabotinov, Opt. Commun. 41(1), 57-88, (1982)). Read more
1984: A strong effect of hydrogen in the copper bromide vapour laser was discovered: small additives of hydrogen in the copper bromide vapour laser result in over double increases in average laser output power and efficiency (D. Astadjov, N. Sabotinov and N. Vuchkov, Effect of hydrogen on CuBr laser power and efficiency, Opt. Commun. 56, 279,(1985)). Read more
1996: A record efficiency of 3.5% for the copper self-terminating lasers was achieved.

A novel electric excitation scheme for the Ne-H₂-CuBr laser has been developed with four distributed capacities to form interacting current circuits (IC – scheme). The IC scheme raises the average output power of the CuBr laser by 40-50% compared with the use of an ordinary scheme that employs a peaking capacitor.

Laser action with copper ions was obtained in a longitudinal nanosecond pulsed Ne-CuBr discharge in the deep ultraviolet on the five lines 248.6, 252.9, 259.7, 260.0 and 270.3 nm. A maximum average output power of 1.3 W was attained totally for the five lines and 0.85 W for the line 248.6 nm. The laser tube lifetime was about 1000h with periodical refreshment of the gaseous mixture. It was found that small admixtures of hydrogen (0.02-0.04 torr) resulted in doubling laser power.


High-power (0.85W) laser emission from copper ions in the deep ultraviolet at the wavelength 248.6nm

Laser action in the deep ultraviolet on the four lines 282.3, 284.7, 289.3 and 291.8 nm was achieved with gold ions in a longitudinal nanosecond pulsed discharge in a He-Au gaseous mixture. A maximum average output power of 0.4 W was obtained totally for the four lines and 0.3 W for the line 282.3 nm. The technology for making the laser tube is the same as that for the self-terminating gold vapour laser excited by a pulsed discharge.

CuBr MOPA (master oscillator-power amplifier) laser system fitted with a generalized diffraction filtered resonator (GDFR) is reported to produce high-quality high-brightness laser emission of throughout-pulse beam divergence as low as 1.06 of the diffraction-limited value. The comparison with typical (stable and unstable) resonator configurations for copper bromide lasers has featured out its high brightness which is, at least, of factor of 2 higher than of the other unstable resonators. This intrinsic characteristic of GDFR-MOPA laser radiation makes it a perfect light source for fine laser applications.


Experimental setup of a CuBr vapour laser MOPA system

A strontium bromide vapour laser excited by a nanosecond pulsed longitudinal discharge has been developed. Optimal discharge conditions for laser oscillation on several atomic and ion lines of Sr have been found. At multiline output a record (two orders of magnitude higher) average laser power of 2.4 W was obtained as more than of 80% of which was concentrated at the 6.45-µm Sr atom line. The results obtained are comparable with those achieved with metallic strontium used as a lasing medium.
A record average laser output power of 11.5 W has been achieved for the self-terminating strontium laser. This laser oscillates on the atomic lines at the wave lengths of 2.06 μm, 2.2 μm, 2.69 μm, 2.92 μm, 3.011 μm, and 6.45 μm, and on the strontium ion lines at the wavelengths of 1.033 mm and 1.096 mm in metallic-strontium vapour excited by a He-Sr discharge The highest output power of 10.3 W was obtained for the infrared line 6.45 μm. The laser pulse recurrence frequency was 17.5 kHz.

The scientific achievements of the Laboratory have contributed to a large extent on the advance of copper self-terminating lasers by including admixtures of halogens and hydrogen in the laser active medium. (N. Sabotinov, Recent progress in copper vapor lasers, invited paper, Proceedings of SPIE Vol. 5120 XIV International Symposium on Gas Flow, Chemical Lasers, and High-Power Lasers, edited by Krysztof M. Abramski, Edward F. Plinski, Wieslaw Wolinski, (SPIE, Bellingham, WA, 2003), 30-37, (2003))
The best results of the laboratory have been obtained with respect to the copper bromide vapour laser, in its invention, research, development and transfer to industry. Good examples of that are the introductions of the CuBr laser into two industrial companies: Pulslight Ltd., Bulgaria and Norseld Pty Ltd, Australia. The first company produces CuBr lasers with output powers of 2W, 3W, 5W, 10W, 40W, 80W and laser systems for the entertainment business, medicine and industry. The last company produces 10W, 20W, 40W copper bromide lasers for medicine and industry.