Title :
THz emission from high-T/sub c/ superconductors by optical pulse excitation
Author :
Hangyo, M. ; Tomozawa, S. ; Murakami, Y. ; Tonouchi, M. ; Tani, M. ; Wang, Z. ; Sakai, K.
Author_Institution :
Res. Center for Supercond. Mater. & Electron., Osaka Univ., Japan
fDate :
6/1/1997 12:00:00 AM
Abstract :
Emission of ultrashort electromagnetic pulses from current-biased superconducting YBCO films has been observed by exciting with femtosecond laser pulses. The emission device is made of YBCO strip lines with a bridge at their center on an MgO substrate. The electric field of the pulse is detected by a photoconductive switch made of LT-GaAs. The emitted pulse width is /spl sim/0.5 psec and its Fourier component extends up to 2 THz. Characteristics of the THz emission such as bias current, pump power and temperature dependence are investigated in detail. The emission mechanism is ascribed to the ultrafast supercurrent modulation caused by the photoexcitation.
Keywords :
barium compounds; high-speed optical techniques; high-temperature superconductors; superconducting thin films; yttrium compounds; 0.5 ps; 2 THz; MgO substrate; THz emission; YBCO film; YBaCuO; bridge; femtosecond laser pulse; high-T/sub c/ superconductor; optical pulse excitation; strip line; ultrafast supercurrent modulation; ultrashort electromagnetic pulse; Bridges; EMP radiation effects; Optical pulses; Photoconductivity; Space vector pulse width modulation; Strips; Superconducting films; Switches; Temperature dependence; Yttrium barium copper oxide;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
