Contactless photoconductive terahertz generation.
We describe a pulsed terahertz (THz) emitter that uses a rapidly oscillating, high-voltage bias across electrodes insulated from a photoconductor. Because no carriers are injected from the electrodes, trap-enhanced electric fields do not form. The resulting uniform field allows excitation with a large laser spot, lowering the carrier density for a given pulse energy and increasing the efficiency of THz generation. Compared to a dc bias, less susceptibility to damage is observed.
JILA, National Institute of Standards and Technology and the University of Colorado, Boulder, Colorado 80309-0440, USA.
H
H
Zhang
J K
JK
Wahlstrand
S B
SB
Choi
S T
ST
Cundiff