Abstract
Comprehensive refractive-index measurements of 3-methyl-4-nitropyridine-1-oxide in the visible and near infrared are reported together with the phase-matching properties for collinear second-harmonic and sum-frequency generations in the principal dielectric planes. Noncollinear second-harmonic generation phenomena in one-beam and two-beam experiments are defined, observed, and subsequently analyzed by means of a simple geometric construction. A thorough investigation of noncollinear phase-matching configurations for second-harmonic and sum-frequency generations is performed and leads to the concept of one-beam noncritical non-collinear phase matching, which may be of great practical interest in optical parametric amplification and oscillation processes.