Lasers ring laser

One variation in dye laser constmction is the ring dye laser. The laser cavity is a reentrant system, so that the laser light can circulate in a closed loop. The ring stmcture provides a high degree of stabiUty and a narrow spectral width. The spectral width of a conventional dye laser on the order of 40 GH2 is narrowed to a value as small as a few MH2. Such systems offer very high resolution in spectroscopic appHcations. 

H.P. Weber, R. Ulrich, A Ihin-film ring laser Appl. Phys. Lett. 1971, 19. 3b. 

Fig. 12.12 Comparison between the shifts in the emitted wavelength of a CBNL and a conven tional ring laser for changes in the ambient refractive index...

Figure 3.25. Laser resonators applicable to molecular glasses A = microdroplet, B = microdisk, C = ring laser, D = vertical cavity distributed bragg laser, E = distributed feedback laser, F = random laser.

We have developed FM lasers based on a commercial ring laser (Coherent 699-21). In this case all the intracavity etalons are removed and replaced by a lithium niobate phase modulator. This modulator can be resonantly driven at a frequency close to the cavity mode spacing. A simple theory of FM operation of a laser suggests that the modulation index is given by [12]... 

Figure 7. Tunable dimer ring laser scheme.

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