Bifurcation and nonlinear dynamics in passive Q-switched optical vortex lasers

Abstract

In a laser resonator with an intra-cavity spiral phase plate, a passive Q-switched pulsed vortex laser carrying a positive unit topological charge is formed by the coherent superposition of the supported off-axis multiple-pass transverse (MPT) resonant modes. Under different pumping conditions, the modal interaction induces spatiotemporal instability and results in periodic and aperiodic oscillations in the vortex laser pulses while the vortex structure remains stable. The constituting off-axis MPT modes that form the vortex strongly overlap in the time domain and can be simulated by a modified Tang–Statz–DeMars model including coherent modal interactions. Expected potential applications using this vortex laser include the manipulation of laser chaos and stochastic events.

Spiral-Phase-Defect Resonator and Its Application in Vortex Laser of Controllable Topological Charges

“…The clear spiral interference patterns in Fig. 5(e), (f) and (g) not only quantifies the topological charge of the +1, -1 and +2 in the optical vortices, which imitate the topological charge of the SPD encoded by the SLM in the laser resonator, but also manifests the high spatial coherence of the vortex laser beam from ASB resonators [26,32].…”

“…To overcome the difficulty, a cylindrical focusing lens was required in the Oron's proposal in 1999 and 2000 [17,18], which restored the broken azimuthal symmetry and swapped back the topological charges. Moreover, a laser cavity with intracavity spiral phase element resonating only off-axis modes was introduced to overcome the singularity [26,32]. In a SPD of finite radius encoded by SLM, broken azimuthal symmetry was introduced into the laser cavity as well.…”