Title :
Free-space electrooptic sampling of terahertz radiation from optically excited superconducting YBa2Cu3O7-δ thin films
Author :
Po-Iem Lin ; Wu, K.H. ; Juang, J.Y. ; Lin, Po-Iem ; Uen, T.M. ; Gou, Y.S.
Author_Institution :
Dept. of Electrophys., Nat. Chiao Tung Univ., Hsinchu, Taiwan
fDate :
3/1/2003 12:00:00 AM
Abstract :
The characteristics of photogenerated terahertz radiation from a current-biased superconducting YBa2Cu3O7-δ (YBCO) bow-tie antenna were investigated using a free-space electrooptic sampling technique. Picosecond electromagnetic pulses about 450 fs wide were obtained. The frequency spectrum derived by Fourier transforming the picosecond pulses spans over 0.1-4 THz. The dynamics of the quasi-particles optically induced by the ultrafast laser pulse primarily determines the performances of the transient terahertz radiation generated under different operating parameters. The results indicate a characteristic quasi-particle relaxation time of about 2.5 ps close to the critical temperature Tc, and a faster time at lower temperatures.
Keywords :
Fourier transforms; barium compounds; electro-optical effects; high-speed optical techniques; high-temperature superconductors; quasiparticles; submillimetre wave antennas; submillimetre wave generation; superconducting thin films; yttrium compounds; 0.1 to 4 THz; 450 fs; Fourier transform; YBa2Cu3O7-δ superconducting thin film; YBa2Cu3O7; bow-tie antenna; free-space electro-optic sampling; frequency spectrum; nonequilibrium superconductivity; optical excitation; picosecond electromagnetic pulse; quasi-particle relaxation time; transient terahertz radiation; ultrafast laser pulse; EMP radiation effects; Electromagnetic radiation; Frequency; Lasers and electrooptics; Optical pulse generation; Optical pulses; Sampling methods; Temperature; Ultrafast optics; Yttrium barium copper oxide;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
DOI :
10.1109/TASC.2003.811033
