Studies On Two New Type High-power He-Ne Laser

The article has reviewed the developed history of the He-Ne laser and introduced the study background and status of the high-power He-Ne laser in brief, and pointed out the important significance in the fields of laser medical etc. Especially to cure cancer by photodynamic action demands the several hundred output-power He-Ne laser. But on the market the He-Ne laser's output-power isn't exceeding 100mW, the inability to produce more high-power has greatly limited the utility of the He-Ne laser. Against this status, in this paper, two design plan of the high-power He-Ne laser are presented, one is a cruciform aperture resonator He-Ne laser, other is a axisymmetric folded-combined resonator He-Ne laser, the former will obtain high output-power with the cruciform aperture structure which can achieve higher gain factor and greater active capacity. And the latter will obtain high power with the system which can achieve greater mode capacity,. composing of two concave-planar-concave resonator and one planar-concave resonator and sharing a planar mirror to output, operating principle and operating characteristic of the He-Ne laser and diffraction loss of Gauss beams which transform though resonator are analysed in terms of theory. Misalignment of a cruciform aperture resonator is discussed. Approximate determination of intra-resonator loss of the misalignment resonator are given, diffraction loss of basic mode and higher-order mode which transform though the resonator is solved. And their output power is estimated. If the misalignment angle of the planar mirror (or the concave mirror) is less than 20" in the cruciform aperture resonator, the average diffraction loss per travel is less than 1% for the TEM03,TEM30 andlower order modes, respectively. Discharging tube is lm long, the short section of the aperture is 4mm long and its long section is 20mm long, the planar mirror transmittivity is l%,the curvature radius of the concave mirror is 3m, the estimated power is 200mW for the cruciform aperture resonator He-Ne laser. If the misalignment angle of the planar mirror (or the concave mirror) is less than 20" in the axisymmetric folded-combined resonator, the average diffraction loss per travel is less then 0.1% for the TEMoi,TEMio and TEMoo modes .respectively. Discharging tubes diameter is 4.5mm, the tube is lm long in the planar-concave resonator and 2m long in the folded resonator, the planar mirror transmittivity is 2.75%, the curvature radius of the concave mirror is 5m, then the estimated power is 189.64mW for the axisymmetric folded-combined resonator He-Ne laser. In addition, an experiment method for adjusting light path and a alignment apparatus accuracy of the axisymmetric folded-combined resonator are discussed in this paper.