Numerical simulation of the w-axicon type optical resonator for coaxial slab CO₂lasers

Abstract

The numerical simulation of the optical resonator for a coaxial slab CO2 laser is conducted. The resonator consists of a toric mirror, a w-axicon, and a plane output coupler. To hold the two slabs coaxially, struts exist in the annular gap region. The effects of the struts on the output power and beam quality for the given resonator are discussed. It is found that varying the vertex of the toric mirror can control the oscillation mode between the E00 fundamental mode and the E01 first azimuthal mode. It is revealed that the resonator loss of the fundamental mode can be smaller than the first azimuthal mode by shifting the vertex inward, and this results in single-mode oscillation at the E00 fundamental mode. On the other hand, the maximum output is obtained under conditions where the resonator oscillates at the E01 mode, because the nodes of the mode coincide with the position of the struts. Loss measurement of each eigenmode well describes the aforementioned phenomena.

The Vector Analysis of the Optical Resonator with the W-axicon for the Coaxial CO2 Laser

“…A definition of the initial electric field was partially coherent as proposed by Bhowmick 5) and used in previous papers on the analysis of the w-axicon resonator. 4) Gain sheet and optical aperture were applied at the surfaces in which struts were placed. The round trip propagation was iterated until the electric field converges.…”

“…[1][2][3] Endo et al have numerically analyzed a resonator with the w-axicon, a toric mirror and a plane output coupler using scalar field analysis. 4) In this method, azimuthal or radial polarization modes are described by the summation of two circular polarizations, however, the solutions are limited to some degree.…”

Generation of Multiple Vortex Beams with Specified Vortex Number from Lasers with Controlled Ince–Gaussian Modes

“…The simulation code of laser oscillation adopted in this study is based on Endo's simulation method, [17][18][19] which could simulate a single-wavelength, single/multi-mode oscillation in unstable/stable laser cavities. [17][18][19] The following is a summary of this method.…”

“…The simulation code of laser oscillation adopted in this study is based on Endo's simulation method, [17][18][19] which could simulate a single-wavelength, single/multi-mode oscillation in unstable/stable laser cavities. [17][18][19] The following is a summary of this method. The method simulates the initial stimulated field with a partially coherent field 20) in the space-frequency domain to avoid dependence between the initial field selection and the conversion field in a stable laser cavity.…”

Vector Analysis of W-Axicon Type Optical Resonator for a Coaxial CO2 Laser

“…[12][13][14] Endo et al have numerically analyzed a resonator with the w-axicon, a toric mirror and a plane output mirror using scalar field analysis. 15) The scalar field analysis is suitable for the resonator consist of w-axicon and toric mirror, on the other hand, we should use the vector analysis for the resonator consist of w-axicon and axicon mirror. In the present study, the authors attempted to use the vector field for the analysis in order to precisely obtain the effect of the inclined surface of mirrors.…”