Title :
THz generation from graphite
Author :
Ramakrishnan, Gopakumar ; Chakkittakandy, Reshmi ; Planken, Paul C M
Author_Institution :
Dept. of Imaging Sci. & Technol., Delft Univ. of Technol., Delft, Netherlands
Abstract :
Subpicosecond terahertz pulses are generated from the surfaces of graphite samples, when illuminated with femtosecond near-infrared laser pulses. Our experiments with highly oriented pyrolytic graphite samples suggest that the emission of THz radiation is caused by photoinduced transient charge carrier movements along the c-axis of the crystal. This is further confirmed by studying the effects of an in-plane magnetic-field which deflects the photocurrent and thereby changes the THz polarization. The experimental results point to two possible generation mechanisms, carrier acceleration in the space charge layer near the graphite surface and/or the photo-Dember effect.
Keywords :
Dember effect; graphite; high-speed optical techniques; microwave materials; photoconductivity; photoemission; space charge; terahertz wave generation; C; THz polarization; THz radiation emission; femtosecond near-infrared laser pulses; in-plane magnetic-field; photo-Dember effect; photocurrent; photoinduced transient charge carrier acceleration; pyrolytic graphite surface; space charge layer; subpicosecond terahertz pulses; terahertz wave generation; Laser excitation; Optical pulse generation; Optical pulses; Optical surface waves; Polarization; Power generation; Radiation detectors; Surface emitting lasers; Ultrafast electronics; Ultrafast optics;
Conference_Titel :
Infrared, Millimeter, and Terahertz Waves, 2009. IRMMW-THz 2009. 34th International Conference on
Conference_Location :
Busan
Print_ISBN :
978-1-4244-5416-7
Electronic_ISBN :
978-1-4244-5417-4
DOI :
10.1109/ICIMW.2009.5324648
