Axicon based conical resonators with high power copper vapor laser

Abstract

We report for the first time the performance of axicon based conical resonators (ABCRs) in a copper vapor laser, with novel results. The unstable conical resonator comprising of conical mirror (reflecting axicon) with axicon angle approximately pi/18, cone angle approximately 160 degrees, and a convex mirror of 60 cm radius of curvature was effective in reducing the average beam divergence to approximately 0.15 mrad (approximately 25 fold reduction compared to standard multimode plane-plane cavity) with output power of approximately 31 W. Extraction efficiency of approximately 50%-60% and beam divergence of <1 mrad was achieved in other stable ABCR configurations using flat and concave mirrors with the axicon. This is a significant improvement compared to 4-5 mrad normally observed in conventional stable resonators in copper vapor lasers. The conical resonators with copper vapor laser provide high misalignment tolerance beta approximately 4-5 mrad where beta is the tilt angle of the conical mirror from optimum position responsible for approximately 20% decline in laser power. The depth of focus d was approximately three times larger in case of conical resonator as compared to that of standard spherical unstable resonator under similar beam divergence and focusing conditions.

Efficient copper vapor laser using metal (Cu, Ag) chlorides in thermal insulation and performance with new prism resonator configurations

“…This may require novel resonator configurations to be explored and implemented in CVLs to meet such requirements. [16][17][18][19] Keeping in view these considerations, new cavity configurations, namely, the prism resonator (stable and unstable) are demonstrated here for the first time in CVL with very high misalignment tolerance of ∼25 mrad and low beam divergence of ∼0.2 mrad with 70%-80% high optical extraction.…”

“…18,19 It is interesting to note that maximum power achieved from prism resonator CVL was ∼35-40 W which is 70%-80% of its maximum (50 W) set power (standard plane-plane cavity) with high misalignment tolerance of ∼25 mrad. Thus, the prism resonator cavity configurations are able to provide low beam divergence (∼0.2 mrad) with high extraction efficiency of 70%-80% and very high misalignment tolerance of ∼25 mrad simultaneously, which otherwise is not possible to achieve from conventional spherical unstable resonators.…”

“…17,[23][24][25][26] Though the CVL was capable of operating at 70 W (plane-plane cavity), it was set to operate at ∼50 W during prism resonator experiments to reduce ASE content and for comparison with other resonators demonstrated by us in past. 13,14,18,19 The CVL was successfully operated with prism resonator configurations as shown in Figs. 6 and 7.…”

Evaluation method for evaluating the surface quality of concave axicons with high reflectivity

“…Axicon lenses have been widely used in applications such as ultra-short laser pulses [1] and experiments with high-power lasers [2,3] due to their minimal optical dispersion and absorption. Normally, axcion lenses are divided into refractive and reflective optical elements.…”