title: Role of misalignment-induced angular chirp in the electro-optic detection of THz waves.
abstract: A general description of electro-optic detection including non-collinear phase matching and finite transverse beam profiles is presented. It is shown theoretically and experimentally that non-collinear phase matching in ZnTe (and similar materials) produces an angular chirp in the χ(2)-generated optical signal. Due to this, in non-collinear THz and probe arrangements such as single-shot THz measurements or through accidental misalignment, measurement of an undistorted THz signal is critically dependent on having sufficient angular acceptance in the optical probe path. The associated spatial walk-off can also preclude the phase retardation approximation used in THz-TDS. The rate of misalignment-induced chirping in commonly used ZnTe and GaP schemes is tabulated, allowing ready analysis of a detection system.
authors.forename: D A
authors.initials: DA
authors.lastname: Walsh
authors.forename: M J
authors.initials: MJ
authors.lastname: Cliffe
authors.forename: R
authors.initials: R
authors.lastname: Pan
authors.forename: E W
authors.initials: EW
authors.lastname: Snedden
authors.forename: D M
authors.initials: DM
authors.lastname: Graham
authors.forename: W A
authors.initials: WA
authors.lastname: Gillespie
authors.forename: S P
authors.initials: SP
authors.lastname: Jamison