title: Detection of freely propagating terahertz radiation by use of optical second-harmonic generation.
abstract: We report the application of electric-field-induced optical second-harmonic generation as a new technique for measuring the field of freely propagating terahertz radiation. Using silicon as the nonlinear medium, we demonstrate subpicosecond time resolution and a sampling signal that varies linearly with the terahertz electric field. This approach, which is attractive for centrosymmetric media, permits a significantly broadened class of materials to be exploited for free-space sampling measurements.
authors: A
authors: A
authors: Nahata
authors: T F
authors: TF
authors: Heinz