We report significant enhancement of second-harmonic-generation intensity i
n a nonlinear optical polymer by strongly confining the fundamental light i
n a planar microcavity. Employing a microcavity formed by a distributed Bra
gg reflector and a silver layer, we have observed up to a factor of 50 incr
ease of second-harmonic light intensity in polymer thin films. (C) 2000 Ame
rican Institute of Physics. [S0003-6951(00)04305-9].