Intensity Correlation Functions of a Non-Q-Switched Laser, Measured by Second-Harmonic Generation

Abstract

The intensity correlation function of the light from a non‐Q‐switched Nd:glass laser has been measured, using an optical gate (OG) to produce second‐harmonic light. The resolution time of this optical gate depends on the differences of the group velocities involved and the crystal length of the optical gate; in the described experimental arrangement a time resolution of about 10⁻¹³ sec is achieved. The effect of thick crystals on the time dependence of the second‐harmonic light intensity is discussed for some special cases. The experimental results are in agreement with the freerunning laser model, namely that a non‐Q‐switched Nd:glass laser has intensity fluctuations similar to thermal light. These results confirm some earlier results which have been achieved by a different technique.