Experimental Observation of a Large Excess Quantum Noise Factor in the Linewidth of a Laser Oscillator Having Nonorthogonal Modes

Yuh-Jen Cheng; C. G. Fanning; A. E. Siegman

doi:10.1103/PhysRevLett.77.627

Experimental Observation of a Large Excess Quantum Noise Factor in the Linewidth of a Laser Oscillator Having Nonorthogonal Modes

Yuh-Jen Cheng, C. G. Fanning, and A. E. Siegman

Phys. Rev. Lett. 77, 627 – Published 22 July 1996

Abstract

Several authors have predicted a substantial excess noise factor $K_{p}$ multiplying the quantum-limited Schawlow-Townes linewidth for laser oscillators having nonorthogonal spatial modes, such as unstable-resonator lasers. Experimental observations of this factor have to date, however, been limited in both number and detail. We report here a detailed experimental measurement of this factor in a diode-pumped hard-edged unstable-resonator Nd:YV $O_{4}$ laser. The measured excess noise factor $K_{p} ≃ 330$ is in reasonable agreement with the theoretically predicted value.