Asymmetric Stationary Lasing Patterns in 2D Symmetric Microcavities

Locking of two resonance modes of different symmetry classes and different frequencies in 2D resonant microcavity lasers is investigated by using a nonlinear dynamical model. The patterns of stationary lasing states and far fields are asymmetric in spite of the symmetric shape of the resonant microcavity. The corresponding phenomenon is actually observed in the experiment of a 2D semiconductor microcavity laser diode.

Figure 1

Resonances of a microstadium cavity. The double and single circles correspond to the resonances of the maximum and second maximum gain.

Figure 2

The wave function of the metastable resonance of (a) the double circle and (b) single circle in Fig. 1. These wave functions are solutions of the linear Schrödinger-Helmholtz equation. The symmetry classes of these modes are, respectively, (a) ${\psi }_{--}(x,y)$ and (b) ${\psi }_{++}(x,y)$. The white curve denotes the stadium cavity.

Figure 3

(a) The difference of the frequencies ${\nu }_1$ and ${\nu }_2$ corresponding to the two lasing modes decreases as the pumping power increases. (b) The asymmetric pattern of the final stable oscillation of the light field.

Figure 4

(a) A trajectory on the ring-type KAM torus in the oval billiard. (b) An asymmetric locking state associated with the ring-type KAM torus.

Figure 5

Schematic diagram of the confocal quasistadium laser diode.

Figure 6

(a) Observed far field pattern at the output power of 10 mW. (b) Calculated far field pattern for the locking state of two modes associated with the ring-type KAM torus.