High-Speed Y–Ba–Cu–O Direct Detection System for Monitoring Picosecond THz Pulses

A high-speed YBa
₂
Cu
₃
O
_7-δ
direct detection system was developed to monitor terahertz picosecond pulses in the time domain. High-T
_C
superconducting thin-film YBa
₂
Cu
₃
O
_7-δ
microbridges with critical temperatures of T
_C
= 85 K were embedded into a planar log-spiral antenna to couple the broadband terahertz radiation (0.1 -2 THz) of several picosecond pulsed sources. The YBa
₂
Cu
₃
O
_7-δ
detectors were installed in a liquid nitrogen cryostat equipped with 18 GHz effective bandwidth readout electronics. THz pulses generated at the electron storage rings ANKA and UVSOR-II have been resolved with a temporal resolution of 30 ps (full width at half maximum) limited by the readout electronics bandwidth. Beam dynamic effects of bursting coherent synchrotron radiation were successfully monitored.