We report the measurement of optically rectified terahertz (THz) wave power relative to the optical excitation area. Rectified THz wave power reaches its maximum when radius <i>r</i> of the optical excitation area is comparable to the center wavelength of the rectified THz radiation. When <i>r</i> is smaller than the center wavelength of the rectified THz radiation, an <i>r</i><sup>2</sup> relationship is demonstrated. A model based on optical rectification and Bethe's diffraction theory is used to describe this relationship.
© 2002 Optical Society of America
(050.1220) Diffraction and gratings : Apertures
(190.7110) Nonlinear optics : Ultrafast nonlinear optics
(320.5390) Ultrafast optics : Picosecond phenomena
(320.7110) Ultrafast optics : Ultrafast nonlinear optics
J. Z. Xu and X.-C. Zhang, "Optical rectification in an area with a diameter comparable to or smaller than the center wavelength of terahertz radiation," Opt. Lett. 27, 1067-1069 (2002)