Half-percent terahertz generation efficiency from cryogenically cooled lithium niobate pumped by Ti:sapphire laser pulses

TL;DR

This study demonstrates a significant increase in terahertz generation efficiency from lithium niobate by cryogenically cooling the crystal to 100 K, achieving 0.5% efficiency with potential for further improvements.

Contribution

The paper reports a more than twofold increase in terahertz conversion efficiency using cryogenic cooling, highlighting the impact of temperature on THz generation in lithium niobate.

Findings

Achieved 0.5% optical-to-THz conversion efficiency at 100 K

Efficiency increased by over 2.5 times compared to room temperature

Cryogenic cooling reduces THz absorption, enhancing efficiency

Abstract

We obtained an optical-to-terahertz (THz) energy conversion efficiency of 0.5% using the tilted-pulse-front technique in lithium niobate at a cryogenically cooled temperature of 100 K pumped by amplified Ti:sapphire laser pulses with ~150 fs pulse duration at 800 nm wavelength. Compared with the optimized conversion efficiency of 0.18% achieved at room temperature, we achieved more than 2.5 times enhancement in conversion efficiency upon cryogenically cooling the crystal due to reduction of THz absorption. Further improvements to the conversion efficiency can be made by optimizing the out-coupling of the THz radiation, transportation of pump energy and by further decreasing the THz absorption in the lithium niobate crystal.