102 6 Resonators with Curved Mirrors

Fig. 6.9. Left : a transverse pattern (near field at the left, far field at the right ) recorded experimentally in a PRO with a nearly confocal resonator. The intracavity aperture was completely open. Right: schematic interpretation of the Fresnel rings in the PRO resonator. The PRO emits in a narrow frequency band, which is related to the wavenumber of the emitted light k = ω/c. The light is radiated at angles such that the longitudinal component of the wavevector matches the longitudinal-mode condition of the resonator

To realize the case of a single-longitudinal mode (but with multiple transverse modes) describable by the CSH equation, the emission was restricted to a single ring by an aperture in the far-field plane. Under these conditions the PRO displayed the typical patterns predicted by CSH equation, which depended on the resonator tuning.

References

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2.M. Brambilla, F. Battipede, L.A. Lugiato, V. Penna, F. Prati, C. Tamm and C.O.Weiss, Transverse laser patterns. I. Phase singularity crystals, Phys. Rev. A 43, 5090 (1991). 95

3.K. Staliunas, G. Slekys and C.O. Weiss, Nonlinear pattern formation in active optical systems: shocks, domains of tilted waves, and cross-roll patterns, Phys. Rev. Lett. 79, 2658 (1997). 96