Intrinsic instability and locking of pulsation frequencies in free-running two-mode class-B lasers

Abstract

We report on recent experimental results of the dynamics of a laser-diode-pumped free-running Nd:YVO 4 laser operating in a two-mode regime. We observe intrinsic quasiperiodic and chaotic oscillations as well as a locking of pulsation frequencies. We perform an asymptotic analysis of model rate equations in which an intensity-dependent cross-gain ͑i.e., nonlinear gain͒ mechanism of direct mode-mode coupling is introduced in addition to the coupling mechanism via cross saturation of population inversions. We show that the intrinsic instability originates from the nonlinear gain mechanism. The observed locking of pulsation frequencies is successfully reproduced by simulations based on the proposed rate equations.

Switchable pulses generation in passively Q-switched multilongitudinal-mode microchip laser

“…Although continuous-wave microchip solid-state lasers are widely used to study the nonlinear effects such as chaos, antiphase dynamics and instabilities [2][3][4][5][6], most of the works are done on the Nd doped gain medium. Coherent, switchable laser pulses with high peak power are required for optical communications and material processing; compact LD end-pumped passively Q-switched solid-state lasers will be potential laser sources for such applications.…”

Farey tree and devil’s staircase of frequency-locked breathers in ultrafast lasers

“…In optics, frequency-locking phenomena have been extensively studied in modulated semiconductor lasers, where an external frequency can be readily coupled to the nonlinear system by using a radio-frequency (RF) source 11 , 15 – 18 , and the hierarchy of the Farey tree and structure of a devil’s staircase can be rather easily observed when tuning the external frequency 11 . Frequency locking has also been demonstrated in other laser structures, such as fibre lasers with external loss modulation 19 or solid-state lasers operating in a two-mode regime 20 . Furthermore, although not explicitly mentioned by the authors, the subharmonic, harmonic, and rational harmonic operation regimes of Kerr microresonators that were reported in refs.…”

Stabilization of class-B broad-area laser emission by external optical injection

“…This class of lasers is of greatest importance for application, as it includes most of the high-demand laser types (solid-state, semiconductors). Class-B lasers exhibit especially complex spatio-temporal dynamics associated with the competition of either longitudinal modes [19][20][21] or transverse modes in smallarea lasers [22][23][24][25]. It was also found that in broad-area class-B lasers filamentary instabilities become especially wellpronounced.…”