Quantum Noise Reduction in Lasers by Dynamic Pump Noise Suppression

Daniel F. Walls, Fritz Haake, S. M. Tan

Weihan Tan

Ulrike Herzog

Carles Serrat, M. C. Torrent, Jordi García‐Ojalvo +1 more

We investigate theoretically the intensity and phase correlations in the quantum-noise-driven dynamics of two spatially coupled microchip lasers. These correlations induce noise reduction phenomena for which simple analytic expressions are derived. We predict a complete suppression of the dominant relaxation oscillation peaks in the intensity difference noise spectrum, as well as photon statistics approaching the standard quantum limit. The correlations and consequent noise reduction effects are robust against frequency detuning and persist for pump powers well above threshold.

Helmut Ritsch, P. Zoller

Xiangming Hu, Zhizhan Xu, Jin-sheng Peng

We study light amplification and quantum noise reduction in a V-type three-level system with two-colour excitation without conventionally irreversible pumping. Employing the equivalent V system in the picture dressed by the pump field coupled to the probe transition, we show that this system exhibits two new features. Lasing with inversion occurs in the regime where the Mollow laser is impossible. The output-intensity fluctuation is suppressed up to 64% below the shot noise limit, which is in contrast to the absence of noise squeezing in the V inversionless laser. More importantly, we identify one irreversible pathway of population transfer to be responsible not only for lasing with inversion between bare states but also for quantum noise reduction. Coherent excitation turns out to be a new way in which one can provide the irreversible pathway for quantum noise reduction.