Page 370 - Tunable Lasers Handbook

330 Norman P. Barnes

A = 2.33907 + 8.20 X lo-’ (T - 25)
B = 2.58395 -10.47 x lo-’ (T - 25)

C = 0.4588 + 1.13 x 10-5 (T - 25)
D = 13.8169 + 7.73 x lo-’ (T - 25)

E = 519.66

A = 2.35084 - 100.78 X lo-’ (T - 25)

B = 2.22518 + 114.47 x 10-j (T - 25)

C = 0.04371 - 0.24 X lo-’ (T - 25)

D = 15.9773 - 107.60 x (T - 25)

E = 741.15

for the ordinary and extraordinary Sellmeier refractive indices, respectively. In these
expressions, temperature T is given in degrees centigrade. Operation at 105°C is
only a small extrapolation of the refractive index data. taken at 25 and 80°C.
In cases where insufficient data are available for complete temperature-
dependent Sellmeier coefficients, the variations of the ordinary and extraordi-
nary refractive indices are given for selected wavelengths [35,37,41,4547]. Far
from the absorption features of the nonlinear crystal. the variation of the refrac-
tive index with temperature is relatively insensitive to the wavelength. Values for
the variation of the ordinary and extraordinary refractive index with temperature
are tabulated in Table 1.
Using the Sellmeier constants listed in Table 5, the phase-matching curves
for Type I phase matching have been calculated for the selected uniaxial nonlin-
ear crystals listed. For these calculations, pump wavelengths are 0.355, 0.532.
1.064, and 2.10 ym. Solid-state lasers make convenient pump sources for optical
parametric oscillators because these lasers can operate either in a cw or a Q-
switched mode. In particular, the Q-switched mode, with its short pulse lengths
and concomitant high peak powers, is conducive to the operation of optical para-
metric oscillators and amplifiers. Pump lasers operating at these wavelengths can
be obtained from a Nd:YAG laser and its harmonics or from either a Ho:Tm:Cr:
YAG or Ho:Tm:Er:YLF laser. Phase-matching curves generated in this manner
are not intended to be an exhaustive compilation of the possibilities but rather
are intended to suggest some of the more common situations. Other possible