Planar waveguide, 1 kW cw, carbon dioxide laser excited by a single transverse rf discharge

Abstract

A transverse radio frequency discharge excited, carbon dioxide slab laser has been operated cw with a hybrid waveguide / confocal unstable resonator to produce an output power of 1.06 kW at 12% efficiency. The active volume of 770×95×2 mm3 consists of a single discharge section with one cable feed.

Efficient multiline nanosecond pulse amplification in planar waveguide CO_2 amplifier for extreme UV laser-produced plasma source

“…Given the waveguide gap just below 2 mm, the waveguide mode filtering (i.e., mode-dependent transmission losses) was expected to be sufficiently strong to maintain high quality of the beam exiting the waveguide, provided the input beam width, radius of wavefront curvature, and launch geometry were engineered such as to match the condition of maximum excitation of the fundamental waveguide mode [11] (1∕e 2 intensity beam width of ∼64% of waveguide gap, near-infinite radius of wavefront curvature at waveguide face, centro-coaxial). In the past, good quality of a beam emitted by a CO 2 slab-waveguide laser with a similar electrode spacing was measured to be M 2 ∼ 1.3 and was found close to a theoretical limit expected for a presence of fundamental waveguide mode only [12].…”

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“…Excess of pump leads to the divergence aggravation. According to the calculations, for the height h2 mm and the same radius of the mirror, the total energy of higher (3,5,7) modes is about 1% of that of the basic mode. The images were taken by the matrix ofphotosensors (SPIRICON production), providing the possibility ofreal-time observation ofradiation power re-distribution from the basic to the nearest third symmetrical waveguide mode.…”

Characteristics of a slab RF-excited CO 2 laser using unstable-waveguide resonator

“…According to this the expressions of transverse intensity distribution of intraresonator radiation for the main (n 1) and the first (n 2) hybride modes are as follows: l(k2 + p2 ) (8) 1+I3W/I, 1+FW/I where integration is by the volume of active medium V = dbl; g, I are gain coefficient for a line centre and saturation intensity; J47, is intraresonator power; k and p are coefficient of losses at the boundaries of active medium and distributed waveguide losses. Inequality (8) shows that saturated gain coefficient of the first hybride mode is less than losses for it. Assuming that g0 and I change little by volume of active medium and changing them for average values from expressions (8) and using (7) we have: (9) where N = jrat ed intraresonator power; X, =°is gain surpassing over losses for n-mode.…”