Noncollinear electro-optic sampling detection of terahertz pulses in a LiNbO$_3$ crystal with avoiding the effect of intrinsic birefringence

TL;DR

This paper presents a novel high-resolution electro-optic sampling method for broadband terahertz waveforms in LiNbO$_3$ crystals that avoids intrinsic birefringence effects by using a noncollinear configuration with a prism-based approach.

Contribution

The study introduces an efficient noncollinear electro-optic sampling scheme in LiNbO$_3$ that eliminates birefringence issues without extra optical components.

Findings

Successful measurement of broadband terahertz waveforms in LiNbO$_3$

Effective velocity matching using a Si prism at the Cherenkov angle

Applicable at probe wavelengths of 800 nm and 1550 nm

Abstract

We propose and experimentally prove efficient high-resolution electro-optic sampling measurement of broadband terahertz waveforms in a LiNbO$_3$ crystal in the configuration with the probe laser beam propagating along the optical axis of the crystal. This configuration allows one to avoid the detrimental effect of strong intrinsic birefringence of LiNbO$_3$ without any additional optical elements. To achieve velocity matching of the terahertz wave and the probe beam, the terahertz wave is introduced into the crystal through a Si prism at the Cherenkov angle to the probe beam. The workability of the scheme at different wavelengths of the probe optical beam (800 and 1550 nm) is demonstrated.