Three-dimensional reconstruction of THz near-fields from a LiNbO$_3$ optical rectification source

TL;DR

This paper presents a novel 3D near-field reconstruction method for THz pulses generated in LiNbO$_3$, enabling detailed characterization of the source’s spatial and temporal properties to improve generation efficiency.

Contribution

It introduces a quantitative 3D near-field imaging technique for THz pulses from LiNbO$_3$, revealing phase front control and near-field dynamics.

Findings

Reconstructed full temporal 3D THz near-field.

Demonstrated phase front tailoring via pump pulse control.

Enhanced understanding of near-field properties for better THz source optimization.

Abstract

Terahertz (THz) generation by optical rectification in LiNbO$_3$ (LN) is a widely used technique for generating intense THz radiation. The spatiotemporal characterization of THz pulses from these sources is currently limited to far-field methods. While simulations of tilted pulse front THz generation have been published, little work has been done to measure the near-field properties of the THz source. A better understanding of the THz near-field properties will improve optimization of THz generation efficiency, transport, and coupling. We demonstrate a technique for quantitative spatiotemporal characterization of single-cycle strong-field THz pulses with 2D near-field electro-optic imaging. We have reconstructed the full temporal 3D THz near-field and shown how the phase front can be tailored by controlling the incident pump pulse.