Laser induced picosecond electrical pulse emission from Tl2Ba2CaCu2O8 thin film devices

It has been demonstrated that superconducting Tl2Ba2CaCu2O8 antennas are capable of generating picosecond electrical pulses following femtosecond optical illumination. The devices are made of 150 nm thick films grown on LaAlO3 substrates. They are patterned into a bowtie antenna structure. The emitted electrical pulses are measured in the far-field by semiconducting photoswitches made of low-temperature grown GaAs. The frequency spectrum of the fast Fourier transformation of the measured signals extends from 40 GHz to nearly 1 THz. The investigated material is the third tight-Tc superconductor which is reported to emit electrical transient signals after femtosecond laser excitation besides YBa2Cu3O7−δ and Bi2Sr2Ca2Cu3O8+δ. The comparison of the signal characteristics emitted from the different materials is interesting for the solid state science and applications of the high-Tc materials.