2 THz bandwidth electrical pulses on Au and YBa2Cu3Ox transmission lines

An amorphous photoconductive GaAs switch is laser ablated directly onto a s uperconducting YBa2Cu3Ox coplanar transmission line structure. Illuminating the switch with femtosecond laser pulses generates electrical pulses conta ining frequency components up to 2 THz. The pulses are detected by photocon ductive sampling and have a full width at half maximum of 0.4 ps without de convolution. Measurements have been performed on both YBa2Cu3Ox and Au/YBa2 Cu3Ox transmission lines and we find attenuation and dispersion coefficient s to be larger on YBa2Cu3Ox at 77 K than on Au. Furthermore, the integrated photoconductive switch is used to demonstrate that subpicosecond pulses ca n propagate through small gaps in the transmission lines with minimum atten uation and dispersion. (C) 1999 American Institute of Physics.