Laser à état solide bi-fréquence sans bruit d’antiphase

National audienceUne réduction de plus de 20 dB du bruit d'antiphase a été obtenue dans un laser bi-fréquence mono-axe sans aucun asservissement d'intensité. Ce résultat repose sur l'utilisation d'un cristal de Nd :YAG taillé selon le plan cristallographique (001) et l'alignement des deux états de polarisation du laser avec deux des axes cristallographiques du Crystal

Experimental demonstration of a dual-frequency laser free from anti-phase noise

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

Oscillation regimes of a solid-state ring laser with active beat note stabilization : from a chaotic device to a ring laser gyroscope

We report experimental and theoretical study of a rotating diode-pumped Nd-YAG ring laser with active beat note stabilization. Our experimental setup is described in the usual Maxwell-Bloch formalism. We analytically derive a stability condition and some frequency response characteristics for the solid-state ring laser gyroscope, illustrating the important role of mode coupling effects on the dynamics of such a device. Experimental data are presented and compared with the theory on the basis of realistic laser parameters, showing a very good agreement. Our results illustrate the duality between the very rich non linear dynamics of the diode-pumped solid-state ring laser (including chaotic behavior) and the possibility to obtain a very stable beat note, resulting in a potentially new kind of rotation sensor

Suppression of Nonlinear Interactions in Resonant Macroscopic Quantum Devices : the Example of the Solid-State Ring Laser Gyroscope

We study the suppression of nonlinear interactions in resonant macroscopic quantum devices in the case of the solid-state ring laser gyroscope. These nonlinear interactions are tuned by vibrating the gain medium along the cavity axis. Beat note occurrence under rotation provides a precise measurement of the strength of nonlinear interactions, which turn out to vanish for some discrete values of the amplitude of vibration. Our theoretical description, in very good agreement with the measured data, suggests the use of a higher vibration frequency to achieve quasi-ideal rotation sensing over a broad range of rotation speeds. We finally underline the analogy between this device and some other macroscopic quantum rotation sensors, such as ring-shaped superfluid configurations, where nonlinear interactions could be tuned for example by the use of magnetically-induced Feschbach resonance

Suppression of Nonlinear Interactions in Resonant Macroscopic Quantum Devices : the Example of the Solid-State Ring Laser Gyroscope

International audienceWe study the suppression of nonlinear interactions in resonant macroscopic quantum devices in the case of the solid-state ring laser gyroscope. These nonlinear interactions are tuned by vibrating the gain medium along the cavity axis. Beat note occurrence under rotation provides a precise measurement of the strength of nonlinear interactions, which turn out to vanish for some discrete values of the amplitude of vibration. Our theoretical description, in very good agreement with the measured data, suggests the use of a higher vibration frequency to achieve quasi-ideal rotation sensing over a broad range of rotation speeds. We finally underline the analogy between this device and some other macroscopic quantum rotation sensors, such as ring-shaped superfluid configurations, where nonlinear interactions could be tuned for example by the use of magnetically-induced Feschbach resonance

Optical levitation using single mode fibers and its application to self-centering of microlenses

International audienceOptical levitation using single mode fibers has been experimentally demonstrated. The use of fibers in levitation experiments presents obvious advantages, in particular, concerning the case with which complicated optical paths can be realized without additional optical components. In addition the microsphere can be accurately deposited on the fiber end by simply controlling the optical guided power. This technique has been used to position microlenses self-centered on the guided mode to improve the coupling efficiency between a semiconductor laser and a single mode fiber