Real-time measurment of the full spatiotemporal field of an single Terahertz pulse by pulsed digital holography

摘要

Up to now, a variety of methods have been developed for the single-shot THz detection, which include spectral encoding technique, optical streak camera, non-collinear geometry spatial encoding, non-collinear cross correlation technique, retrieval algorithm based on in-line spectral interferometry, two-dimensional electro-optic imaging with dual echelons, tilted front collinear geometry, etc.rnFor a single-shot characterization of THz pulse, all of the schemes mentioned above can be, however, only employed to measure the electric field of a single-shot THz either in its spatial or temporal domain, respectively, in real time.rnIn this paper, we describe a method for a single-shot recording of the full spatiotemporal electric field, E(x, y, t), of freely propagating terahertz pulse based on the electro-optic (E-O) sampling technique and the pulsed digital holographic approach. From a series of sub-holograms recorded digitally, the complete THz electric field E(x, y, t) can be recovered by the following digital reconstruction algorithm. The spatial and temporal resolutions are limited by the wavelength of terahertz pulse and the probe pulse duration, respectively. Our new method will open a possibility of a full characterization of the three-dimensional THz field E(x, y, t) in a single-shot mode.