Experimental demonstration of a dual-frequency laser free from antiphase noise

Abstract

A reduction of more than 20 dB of the intensity noise at the anti-phase relaxation oscillation frequency is experimentally demonstrated in a two-polarization dual-frequency solid-state laser without any optical or electronic feedback loop. Such a behavior is inherently obtained by aligning the two orthogonally polarized oscillating modes with the crystallographic axes of a (100)-cut neodymium-doped yttrium aluminum garnet active medium. The anti-phase noise level is shown to increase as soon as one departs from this peculiar configuration, evidencing the predominant role of the nonlinear coupling constant. This experimental demonstration opens new perspectives on the design and realization of extremely low noise dual-frequency solid-state lasers.

Optically pumped VECSELs: review of technology and progress

“…The class-A operation of VECSELs has also received significant attention in generating simultaneous dual-wavelength operation [284][285][286][287], i.e. producing two orthogonal frequency components that are spatially separated at the gain mirror, using an intracavity birefringent plate.…”

Theoretical and experimental analysis of intensity noise correlations in an optically pumped, dual-frequency Nd:YAG laser

“…Indeed, in such a crystal, the emitting dipoles can be approximated as if they were aligned along the crystallographic axes of the gain medium [13]. This has recently proved to be useful in controlling the coupling between the two lasing modes by aligning their polarizations along two orthogonal crystallographic axes of the h100i-cut Nd:YAG crystal [14].…”

“…In the present paper, we thus investigate, both theoretically and experimentally, the relative intensity noise (RIN) spectra and also the correlation between the intensity noises of the two lasing modes for different coupling situations. In our laser, which is based on a h100i-cut Nd:YAG crystal gain medium, different coupling strengths between the eigenpolarization modes can be achieved by varying the eigenpolarization directions with respect to the crystallographic axes [13,14]. In Section 2, we start by developing a theoretical model.…”

Experimental and theoretical studies of a dual-frequency laser free from anti-phase noise

“…This has been illustrated in the case of a Nd:YAG crystal in which the choice of a (100)-cut crystal together with the proper orientation of the polarizations of the laser modes permit to cancel this resonance by more than 20 dB [3]. Besides, the coupling constant between the two modes being easily adjustable in this laser, we have investigated both experimentally and theoretically the behaviour of the correlation between the intensity noises of the two orthogonally polarized modes.…”