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<title>Effect of bandwidth on beam smoothing and frequency conversion at the third harmonic of the Nova laser</title>

1993; SPIE; Volume: 1870; Linguagem: Inglês

10.1117/12.154483

1996-756X

Deanna M. Pennington, Mark A. Henesian, S. N. Dixit, H. T. Powell, C. E. Thompson, Timothy L. Weiland,

Laser-Matter Interactions and Applications

We present the results of experiments performed on the Nova laser system to determine the effect of bandwidth on third harmonic (3(omega) ) frequency conversion and beam smoothing by spectral dispersion (SSD). Our experiments utilized a wide bandwidth fiber optic cross- phase modulated (XPM) source and a narrower bandwidth microwave modulated (FM) source, each centered at 1053 nm (1 (omega) ). A significant fraction (> 50%) of the 1(omega) XPM bandwidth was transferred to the 3(omega) beam (22 cm -1 yields 36 cm -1 ), yielding 0.13% bandwidth at 3(omega) . The maximum intrinsic narrowband 3(omega) frequency conversion obtained using a type-II/type-II KDP crystal array was 62%. The intrinsic efficiency obtained at the Nova 10-beam chamber is typically > 65%. Frequency conversion was essentially unaffected by the 2 cm -1 bandwidth obtained from FM source. However, the 5 - 16 cm -1 of bandwidth from the XPM source reduced the conversion efficiency to approximately 24%. We have developed broadband frequency conversion codes and broadband pulse simulations to model our results, and have obtained good agreement with experiment.