We demonstrate a simple quasi-optical technique for spatiotemporal shaping of half-cycle terahertz-radiation pulses. We show, both experimentally and theoretically, that properly polarized half-cycle pulses can be modulated temporally by diffraction through a conductive aperture of finite thickness. We use the finite-difference time-domain method to solve Maxwell’s equations for such a geometry and show that it can explain all the experimentally observed features. In the case of a thick aperture, a planar waveguide model can also be used to describe the propagation of the pulse through the aperture, with excellent agreement with the experimental results.
[Optical Society of America ]
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