Tadeusz M. Adamowicz

Generation of the infrared laser oscillations in the He-Cu sputtered systems excited by RF discharge

In this paper experimental results on infra-red laser oscillations in the He-Cu sputtered systems excited by an rf discharge (13.5 MHz) are reported. The results of the small- signal gain measurement of the infra-red He-Cu4 laser lines are presented.

Method of measuring active-medium and resonator parameters in sputtered hollow cathode discharge (HCD) He-Cu lasers

A new method has been developed for direct measurements of unsaturated and saturated gain in lasing media as well as optical losses in laser resonators. The saturation parameter can be determined if single-frequency laser performance is achieved. This method has been successfully applied to measure and compare lasing features of the media created in sputtered hollow cathode discharge (HCD) copper ion lasers operating on 780.8 nm transition.

Study of lasing and discharge plasma parameters in noble gas/metal atom mixtures

Results of research on metal ion lasers are presented. They were obtained using novel diagnostic methods for measurements lasing parameters of noble gas-metal vapor systems and determination of metal atom diffusion coefficients in noble gases. Influence of helium 3He isotope on plasma and laser parameters in He-noble gas and metal atom mixtures was studied as well as some elementary processes in noble gas discharges for laser generation.

Influence of 3He isotope on laser generation in a hollow-cathode He-Cu ion laser

The influence of 3He isotope on laser performance of a sputtered segmented hollow cathode discharge He-Cu ion laser oscillating on 780.8 nm transition is presented. At low currents the laser power and small-signal gain are higher for 3He than for 4He. At higher discharge currents the laser parameters are similar both isotopes. However, due to lower discharge voltage for 3He, the same laser output power is obtained at small electrical input power.

Operating characteristics of a hollow-cathode Ag II ion laser

In this paper we repot efficient laser oscillation on the IR 840.4 nm Ag II transition in a He-Ag laser with high voltage 3 mm I.D. and 20 cm long helical hollow cathode. Small- signal gain coefficient of about 60 percent/m for that line was measured at the discharge current 2 A. A similar gain was reported in a conventional HCD at about 10 times higher linear discharge current density. The Ag II 840.4 nm laser transition was found to be homogeneously broadened.

Influence of the 3He isotope on the output parameters of the He-Kr hollow cathode laser

The influence of the 3He isotope as a buffer gas on the operating characteristics of the He-Kr hollow cathode laser is studied. A comparison of the laser output power and gain on the KrII 469.4 nm and KrII 431.8 nm lines in 3He-Kr and 4He-Kr gas mixtures is made and an increase of 33% is observed in the case of the 3He-Kr gas mixture. A simple qualitative analysis of the plasma kinetics shows that the observed increase of the laser output parameters is due to the increased rate constant for the excitation transfer reaction and the increased density of the He(2 3S1) metastable atoms and Kr ground state ions. The main reasons for this are the higher mean relative velocity of the colliding particles and the higher rate of electron cooling in 3He-Kr plasma. Peak output powers of 10 W and 1.5 W and small signal gains over the losses of 85% m-1 and 64% m-1 are measured for the blue and violet lines, respectively, from a 21 cm active length at 17.5 kPa 3He pressure, 17 Pa Kr pressure and 96 A peak current. These values are significantly higher compared to earlier investigations. The operating discharge conditions are enlarged considerably; up to 21 kPa He pressure and 100 A peak current. The laser design chosen contributes to the achievement of this goal.

Diagnostics of hollow cathode discharge metal ion lasers

Lasing properties of active media in sputtered hollow cathode discharge (HCD) He-Cu lasers operating on 780.8 nm transition have been investigated for several HC configurations. Direct measurements of small-signal gain and its spatial distribution have proved that a segmented hollow cathode discharge (SHCD) is the most efficient in achieving laser action on metal ions excited by thermal energy charge-transfer reaction. Results obtained for He-Cu lasers indicate that the observed linear dependency of gain on discharge current can be explained by limited flow of metal atoms into the region of laser generation and probably are valid for all kind of sputtered metal ion lasers oscillating on UV and IR transitions. The possibility of obtaining continuous or long-pulse laser operation in far UV range is also discussed. A new method of measuring diffusion coefficients of metal atoms in noble gases in sputtered HCD lasers is presented.

Measurements of active-medium parameters in sputtered hollow cathode discharge (HCD) copper ion lasers

Lasing properties of active media in hollow cathode discharge (HCD) He-Cu lasers operating on 780.8 nm line have been investigated for different kinds of hollow cathode geometries. Direct measurements of unsaturated and saturated gain, optical losses in the laser cavity and laser output power vs. resonator coupling carried over the wide range of excitation and filling conditions enable us to compare different laser media. The highest small-signal gains equal to 40%/m for a 2.5 X 6 mm rectangular slot cathode and 43%/m for a 3 mm I.D. helical cathode have been found within the pressure range where the most efficient hollow cathode effect occurs. From gain vs. oscillator intensity dependence, the saturation intensities have been calculated for a homogeneously broadened line. They increase linearly with helium pressure, hence more efficient laser operation can be obtained at higher pressures than required for the highest gain.

Device with krypton lasers for diagnostics and therapy of tumors

In this paper a unit with two krypton lasers is described. This apparatus is designed to be used in photodynamic diagnosis and therapy of tumors in ophthalmology. Some technical data are given.

Ophthalmic endocoagulator with argon laser

An endocoagulator with an ion argon laser designed and manufactured at Warsaw Technical University is described in this paper. Technical data and a short description of this unit are given.