Retracing behavior of phase matching has been observed in the generati
on of infrared radiation (1.25-1.85 mum) by both type-I angle-tuned an
d temperature-tuned difference frequency mixing of a Nd:YAG laser (106
4 nm) with its second-harmonic pumped dye laser (570-675 nm) in lithiu
m triborate crystal. Large spectral acceptance of 49 nm at spectral no
ncritical phase-matching point and angular acceptance of 4.0-degrees a
t angular noncritical phase-matching point has been obtained.