Tilted etalon

Fig. 5.35. Single-mode operation by inserting a tilted etalon inside the laser resonator...

Fig. 5.41. Mode selection in the cw dye laser with a folded cavity using a birefringent filter, a tilted etalon, and a prism FPI (Coherent model 599). The folding angle is chosen for optimum compensation of astigmatism introduced by the dye jet...

A HeNe laser with an unsaturated gain of Go(vo) = 1.3 at the center of the Gaussian gain profile has a resonator length of J = 50 cm and total losses of 4%. Single-mode operation at vq is achieved with a coated tilted etalon inside the resonator. Design the optimum combination of etalon thickness and finesse. 

M. Hercher Tilted etalons in laser resonators. Appl. Opt. 8, 1103 (1969)... 

The thickness t of the etalon should be small in order to minimize walk-off losses by the tilted etalon. If we assume as a reasonable number t = 0.5 cm,... 

The walk-off losses limit the tuning range of tilted etalons within a laser resonator. With increasing angle 3 the losses may become intolerably large [4.24b]. 

With a tilted etalon inside the resonator of a singly resonant cavity, single-mode operation can be achieved. Frequency stability of a few MHz has been demonstrated [7.94],... 

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