1550 nm compatible THz photoconductors

An ErAs:InGaAs photoconductive receiver in a continuous-wave THz setupA
An ErAs:InGaAs photoconductive receiver in a continuous-wave THz setupA

REPHCON aims for the development of Rare Earth-enhanced Photoconductors for Terahertz generation and detection driven by telecom wavelength lasers. Photoconductors are optically switched resistors with a recovery time in the range of 1 ps and below. A laser signal, either consisting of two continuous-wave lasers that are detuned by the THz frequency or a single pulse laser with a spectral width of several THz, modulates the resistivity of the photoconductor. If the photoconductor is used as source, an applied DC bias results in an AC current at the THz frequency. If employed as a receiver, a received THz signal by an antenna biases the THz-modulated resistor with a THz bias. This results in a mixing process with a DC component. Unlike other THz mixers, there appear no harmonics. A photoconductor is thus an ideal mixer as long as it is not saturated. The project is supported by the Deutsche Forschungsgemeinschaft (REPHCON, PR1413/3-1 and PR1413/3-2)


Project responsible: Sascha Preu
Team members:
Uttam Nandi (PhD student) predominantly develops pulse photoconductive sources and detectors operated with 1550 nm lasers.
Further Bachelor and Master students support the project (past and ongoing):
  • Felix Schmidt Brand (Bachelor student, large area emitters)
  • Melika Rateghi (Master student, noise reduction techniques)
Collaboration partners:
  • Gregor Koblmüller, TU München
  • Hong Lu, Nanjing University, China
  • Arthur C. Gossard, University of California, Santa Barbara