Bright MM-Wave and THz Luminescence by Down-Conversion of Near-IR Amplified-Spontaneous-Emission

We report the measurement of exceptionally bright, incoherent radiation in the THz region by frequency down-conversion of amplified spontaneous emission around 775-nm wavelength. The down-conversion technique is optical mixing in an interdigital photoconductive capacitor made from ultra fast ErAs:GaAs. The brightness temperature into a single spatial mode is approximately 1.1×105 K, making the new radiation at least 70 times more intense than common incandescent sources in the THz region.