Relative strength of second harmonic and 3/2 omega emissions from long-scale-length laser produced plasmas
Experiments were conducted on the planar slab targets of carbon, aluminum, and copper using a 1.0641-micron laser at laser intensities varying from 2 x 1012 to 1 x 1014 W/cm2. The laser had a fluorescent linewidth of 4.5 A. Spectral profiles of parametrically modulated second-harmonic as well as 3/2omega(0) emissions have been measured for the long-scale-length plasmas so generated. Relative strengths of these emissions with respect to peak signal intensity and spectral energy content as a function of laser intensity are graphically reported. Results are discussed on the basis of two plasmon and parametric decay instabilities.