The properties for members of a new class of nonlinear optical (NLO)
materials which stoichiometrically incorporate organic and inorganic
constituents into a single crystalline lattice are reported. Recent results
for our synthetic, crystal growth, and optical studies suggest that a number
of these relatively transparent “semiorganic” compounds have significant
second and/or third order NLO responses and often display favorable crystal
The prototype material of this class, zinc tris(thiourea) sulfate, or ZTS,
has a UV cutoff at about 325 nm, can be readily grown to cm3
sizes, and has been shown to be a highly efficient Type II frequency doubler
for 1064 nm Nd:YAG laser radiation. ZTS also possesses a moderate third
order nonlinear optical response (ca. 0.1 × CS2) which occurs on
at least a picosecond time scale as determined by degenerate four-wave
mixing (DFWM) experiments at 532 nm.
Refractive index, second harmonic generation, and DFWM data for a number of
these new compounds are presented.