| Our group purchased a THz photomixer from the Millimeter Wave Technology Group at the Rutherford Appleton Laboratory in London, UK. A photomixer is based on optical heterodyne conversion where a photoconductor or photodiode is illuminated by two laser beams with a difference frequency in the THz region. The beat frequency of the two lasers will modulate the conductivity of the photomixer material. The variation of the conductivity is converted to electrical current and finally radiation by applying a bias voltage across the active region of the device. My thesis concerns the determination of the characteristics of the photomixer, which is an expensive and extremely sensitive piece of equipment, to optimize its performance in support of a number of research activities within the group. |
