Transverse Structure Formation and Vortices in Lasers
Until the end of the last decade, studies on laser behavior have focused on the purely temporal laser dynamics. The motivation was to understand single-mode laser instabilities which had been observed in various laser systems. It is known that a laser is a nonlinear dynamical system which exhibits dynamic phenomena such as periodic instabilities, chaos, bistability and multistability which are also observed in other nonlinear dynamical systems such as are mechanical, chemical, biological, hydrodynamical and other optical systems. Initial work on the transverse spatial structure formation of the laser treated the spontaneous spatial symmetry breaking leading to a stationary transverse pattern. It is possible to produce stationary spatial patterns when transverse modes of slightly different frequencies are excited. This is possible by 'cooperative frequency locking' where the different transverse modes are phase synchronized to a common frequency. Modes of different transverse families can lock to different frequencies.