Title :
High-intensity terahertz pulses at 1-kHz repetition rate
Author :
Budiarto, E. ; Margolies, J. ; Jeong, S. ; Son, J. ; Bokor, J.
Author_Institution :
Dept. of Electr. Eng. & Comput. Sci., California Univ., Berkeley, CA, USA
fDate :
10/1/1996 12:00:00 AM
Abstract :
We report the generation of terahertz pulses with 0.4-μJ pulse energy at 1-kHz repetition rate using a large-aperture GaAs photoconductor with 3-cm gap aluminum electrodes, biased at voltages up to 45 kV. The terahertz output energy saturates at a laser fluence of 40 μJ/cm2 at low-bias fields, while no clear saturation point was observed at high-bias fields. The output was found to be dependent on the repetition rate: at high fluences, pulse energy at 1 kHz is higher than that at 100 Hz by as much as 60%. A study of the behavior of the terahertz pulse energy and pulsewidth as a function of the pulsewidth of the laser excitation was conducted and compared with theoretical predictions. Propagation properties of the terahertz beam were also characterized, leading to a focal spot size as small as 800 μm at the focus of a 2.5-in focal length parabolic mirror
Keywords :
electrodes; gallium arsenide; infrared sources; laser beam effects; laser mirrors; optical saturation; photoconducting materials; μJ pulse energy; 0.4 muJ; 2.5 in; 45 kV; 800 mum; GaAs; cm gap aluminum electrodes; focal length parabolic mirror; focal spot size; high fluences; high-bias fields; high-intensity terahertz pulses; kHz repetition rate; large-aperture GaAs photoconductor; laser excitation; propagation properties; pulse energy; pulsewidth; repetition rate; terahertz beam; terahertz output energy saturation; terahertz pulse energy; terahertz pulses; Aluminum; Electrodes; Gallium arsenide; Laser excitation; Laser theory; Optical pulse generation; Optical pulses; Photoconductivity; Space vector pulse width modulation; Voltage;
Journal_Title :
Quantum Electronics, IEEE Journal of
