Efficient second-harmonic generation with broadband laser pulses.

Unexpectedly efficient second-harmonic generation (~10%) in KDP was observed with a broadband dye-laser source having a 1.4-nm bandwidth. The observations are explained by a frequency-mixing effect in addition to simple doubling of frequency. The measured second-harmonic output bandwidth is as narrow as 0.21 nm. The present experiment affords the possibility of generating narrow-band tunable UV laser pulses with high efficiency.