Piotr Warda

Analysis of influence of buffer gas admixtures on laser generation conditions in noble gas ion lasers

In the previous our paper we have presented measurement results of the phenomenon of argon additions influence on output parameters of krypton ion lasers. In that paper we have described that small argon admixtures to the krypton discharge increase the laser output power of several krypton laser lines. In actual paper we present following measurement results of this phenomenon. We have observed that neon admixtures cause much stronger effect on krypton laser lines than we have previously observed with argon admixtures. We have also observed the positive influence of neon additions on generation conditions of argon laser lines. The magnitude of this effect is weaker than influence observed with krypton laser lines however the way of the effect is identical. This confirms our explanation of this phenomenon described in. Results presented in actual paper were performed in wide range of mixture compositions, gas pressures and discharge current values for several argon and krypton laser lines.

Analysis of simultaneous generation of argon and krypton laser lines in ion lasers filled with argon-krypton mixture

Argon ion lasers can generate several strong laser lines in short wavelength region of visible spectrum (green and blue light). Krypton ones offer the generation of laser lines in long wavelength region (red and yellow light). Both gases have complementary generation ranges thus ion lasers filled with mixture of argon and krypton are attractive laser sources for many applications. In most of these applications the only one laser line selected with dispersion element within the resonator are used at one time. After removing the dispersion element the simultaneous generation of many wavelengths is possible. Unfortunately in this working mode of ion lasers the negative effect of competition between laser lines appears. The effect has the most significant influence on the generation of yellow Kr II 568 nm line which is very needed for some applications due to small number of other available strong laser sources for this light range. Generation conditions of this line is strongly hampered when ion laser simultaneously generates other laser lines thus in this laser working mode this laser line completely disappears. We have observed the exact reason of this effect and we have described the way to improve laser generation conditions of Kr II 568 nm line which makes possible to obtain the laser generation of this line simultaneously with other laser lines.

Argon-krypton ion laser as light source for medical photocoagulation applications

Photocoagulators are one of the most popular laser devices in medicine. Due to different kind of interaction of particular wavelength range of laser light with live tissues, sources of laser radiation which can cover as much as possible of visible spectrum are still very wanted (see [1,2]). In last years it also can be observed the intensive developing works on new photocoagulation technique called “micropulse coagulation” [3,4]. The most critical feature of lasers for micropulse coagulation is the possibility of fast switching between two selected laser power values. It seems that the good proposal for these applications can be ion laser filled with argon-krypton mixture. Authors previously have indicated the possibility of improvement of generation conditions in this type of laser in presence of buffer gases [5,6] and with use developed by authors pulse supply regime [7,8]. These improvements allow to obtain output power values of most important argon and krypton laser lines in laser filled with mixture of both gases, similar to values available in laser filled with pure gases. Presented in this paper the following researches are concerned on verification of possibilities of use of the developed laser system in photocoagulation with possibility of use of the laser system in micropulse coagulation technique.

Ion argon-krypton laser for medical applications

Ion gas lasers filled with pure argon or krypton are often used in medicine. The number of possible medical laser applications are still increasing. Every type of application requires specific wavelength range. Due to number of available laser wavelengths of argon and krypton lasers, laser filled with mixture of both gases could be interesting universal medical laser source. However output power value of some interesting in medical point of view laser wavelengths may be insufficient in laser filled with mixture. Developed by authors quasi-continuous ion laser supply regime in connection with observed and described by authors the effect of laser power increase in presence of noble gas admixtures allows to achieve laser power satisfactory for certain medical applications but unavailable in typical ion lasers operated with standard continuous power supply regime.

Influence of noble gas additions on the output power of krypton ion laser

In this paper authors will present the phenomenon of advantageous influence of noble gas additions on the output parameters of krypton ion lasers. Authors have observed that small additions of argon to the krypton discharge causes increase of laser output power of certain krypton laser lines. The power change depends on laser line wavelength, mixture composition, gas pressure and discharge current values. Authors will present measurement results and explanation of this phenomenon.

Current pulse operation of an argon-krypton ion laser

In many applications of ion gas lasers the laser beam is used for specified short periods of time. For these applications laser systems are typically equipped with mechanical shutter. In consequence of this regime of laser beam modulation the peak output power of laser pulses are equal to constant output power generated by laser. Results of our experiments described in 1 shows that in pulse mode of supplying discharge current it is possible to obtain significant increase of peak value of laser output power in comparison with laser output power generated in CW operation (without current modulation). In this paper we present results of our following experiments on pulse supply of ion laser filled with argon-krypton mixture. For this laser operates in pulse regime we have observed the significant - up to 3.5 times - increase of peak laser output power. This effect was especially strong in the UV range. This paper anwe measured in far field the sigxture percentage on the output power of individual Ar and Kr spectral lines in pulse operation. The research suggests that the most significant effect results from different gas pumping rate of the mixture components in the discharge path.a

Properties of the noble gas ion lasers in multi-pulse operation

Argon and krypton ion lasers work typically in CW (continuous wave) mode. In many of applications, the continuous operation of ion lasers is not required. Presented in this article laser power supply makes possible to operate in two regimes: continuous and quasi-continuous (multi-pulse). In multi-pulse operation the most of output power limits for continuous regime was overcame. This allowed increasing the laser output power considerably. Particularly excellent results were obtained for laser tube filled with Ar-Kr mixture and operating in UV range. The main phenomenon deciding on output laser power increasing in pulse and multi-pulse operation is minimization of harmful effects of gas pumping. Possibility of multi-pulse operation creates new advantages of ion lasers and extends range of its applications.

New method of power enhancement of argon ion laser

A positive effect of application of permanent magnets field in argon ion laser has been observed. Some ring magnets producing quasi-homogeneous field increases several times the output power. This influence is stronger with respect to magnet coil application. The reason of this phenomenon is caused by electron temperature increasing in radial magnetic field areas. Application of permanent magnets field should substantially enhance the output power of air cooled argon lasers.

Air-cooled argon laser with permanent magnets

Introducing the quasi-homogenous axial magnetic field from permanent magnets to metal- ceramic argon discharge tube it is possible to increase considerably the output power of laser. This power is approximately close to the output power of laser with a classical magnet coil. The use of permanent magnets allows it to apply an air cooling system. The cw power of air cooled argon laser with active medium length 320 mm is about 2 W and increases to 3.5 W in pulsing excitation.

Influence of crystal Brewster windows on decreasing the Faraday rotation effect in argon ion lasers

Application of an axial magnetic field in ion argon lasers causes rotation of the polarization plane of output radiation. This fact increases the optical losses of the resonator. This effect can be reduced remarkably by using the crystal quartz Brewster windows instead of the fused silica ones. A Faraday effect can be calculated with the help of Jones matrix formalism. It has been shown that by using crystal quartz windows we can decrease the optical losses 10 times in comparison with the fused silica windows. This effect has been confirmed experimentally.