GaSe crystals for broadband terahertz wave detection

A broad bandwidth detector for use with a coherent optical source to measure intensity information of terahertz (THz) frequency pulses which have a THz pulse period, each THz pulse having a THz pulse width, the broad bandwidth detector comprising:

• coupling optics optically coupled to the coherent optical source to direct a probe optical beam produced by the coherent optical source along a probe beam path substantially collinear with a pulse beam path of the THz frequency pulses;
• a GaSe substrate having a first surface and a second surface substantially parallel to the first surface, the GaSe aligned such that the probe beam path intersects the first surface at a phase-matching angle and a probe polarization of the probe optical beam is varied based on interactions between the probe optical beam and the THz frequency pulses within the GaSe substrate;
• a polarization detector aligned in the probe beam path to detect the varied probe polarization of the probe optical beam;
• and
• calculation means electrically coupled to the polarization detector to determine the intensity information of the THz frequency pulses based on the detected probe polarization of the probe optical beam.