A single-mode laser beam is partially not coherent in nature. By expressing such single-mode beam as an array of square-root damping waves, we have deduced a factor that demonstrates incoherence influence of single-mode pump on second-harmonic generation. This factor is analytically formulated as a function of the ratio of crystal length and laser coherence length. When this ratio is smaller than 1.1, the value of the factor is above unity with a maximum of 1.253, indicating the existence of enhancement effect of single-mode pump on its second-harmonic intensity.
© 1996 Optical Society of AmericaPDF Article