Investigation and Application of Ultrafast Photoresponse of YBa2Cu3O7−δ Microbridges Excited by High Fluence Optical Pulses

Ultrafast photoresponse of dc-biased optically-thick YBa2Cu3O7−δ microbridges at T < Tc triggered with 100 fs optical pulses of high fluence was investigated by means of sampling oscilloscope and approach of a S-(1.5– 4 GHz) & C-(4–7 GHz) frequency-band antenna radiation, excited by the photoresponse. A superposition of ultrafast(photokinetic) and slow(bolometric) components of the photoresponse caused a quadratic rise of Fourier amplitude of the radiation with a laser fluence increase. The maximum of the radiation amplitude was obtained at T = Tc− 9.2 K and a repetition rate of the transmitting-antenna decreased from 180 to 20 MHz, when laser fluence was increased from 5 to 40 mJ cm−2/pulse. A method for optically-thick photoswitches triggering with high fluence optical pulses is demonstrated and discussed.