Spatiotemporal measurements of a near-single-cycle terahertz pulse emitted from a photoconductive switch terahertz (THz) source show the effects of spherical aberration and surface waves on the pulse shape. The measured phase front has a swallow-tail shape described by catastrophe theory that contributes to the concentric ring structure of THz beam profiles. A time-of-flight model shows that the pulse shape is due to propagation along a cusp caustic and enhancement of the wings of the swallow-tail pulse is caused by surface waves.
© 2005 Optical Society of America
M. T. Reiten and R. A. Cheville, "Effect of spherical aberration and surface waves on propagation of lens-coupled terahertz pulses," Opt. Lett. 30, 673-675 (2005)