Highly efficient generation of 02 mJ terahertz pulses in lithium niobate at room temperature with sub-50 fs chirped Ti:sapphire laser pulses

Abstract

We demonstrate generation of 0.2 mJ terahertz (THz) pulses in lithium niobate driven by Ti:sapphire laser pulses at room temperature. Employing tilted pulse front technique, the 800 nm-to-THz energy conversion efficiency has been optimized to 0.3% through chirping the sub-50 fs pump laser pulses to overcome multi-photon absorption and to extend effective interaction length for phase matching. Our approach paves the way for mJ-level THz generation via optical rectification using existing Ti:sapphire laser systems which can deliver Joule-level pulse energy with sub-50 fs pulse duration.

Efficient terahertz generation in highly nonlinear organic crystal HMB-TMS

“…The study of linear and nonlinear THz light-matter interactions has enabled the observation of intriguing physics such as insulator-to-metal phase transitions in correlated electron materials [3], spectroscopic studies of nonlinear rotational dynamics of gas-phase molecules [4,5], vibrational dynamics in solids and liquids [6,7], spin dynamics in magnetic materials [8][9][10], and very recently, multidimensional THz spectroscopy of these rotational, vibrational and spin degrees of freedom [11][12][13]. In these examples, the THz sources are often based on optical rectification (OR) of femtosecond (fs) laser pulses in LiNbO 3 crystals which is capable of generating strong THz pulses with energy approaching mJ [14][15][16][17]. However, certain drawbacks exist in LiNbO 3 -based THz sources.…”

Multimillijoule coherent terahertz bursts from picosecond laser-irradiated metal foils

“…Via optical rectification, a maximum THz energy of 436 and 900 μJ has been generated from lithium niobate (LN) (15) and organic crystals (16, 17), respectively. Due to the inherent optical damage of crystals, one has to increase the size of both crystals and the pump spot for higher THz energy (18, 19). However, hurdles in the growth of large-size high-quality crystals and the inherent multiphoton absorption effect of crystals limit the potential of higher energy output in crystal-based THz sources.…”

Development of intense terahertz light source for forming periodic structures on material surface

“…The maximum terahertz energy of 119 µJ was obtained with SLN at maximum laser fluence of 25 mJ/cm 2 (energy: 40 mJ). Efficiency tended to saturate with higher laser fluence but reached 0.29%, which is the world's best result that outperforms previous research 11 . On the other hand, maximum energy for CLN was 110 mJ; that is, SLN featured efficiency higher by 8.2% than that of CLN.…”

“…This can be explained in the following way: as laser fluence grows, carriers (free electrons and holes) are generated via multiphoton absorption to damp terahertz waves 15 . The value of 0.29% is higher than in previous study, 11 and this result is noteworthy as terahertz generation at the world's highest efficiency.…”

“…Based on the above, LIPSS formed with terahertz radiation are advantageous over those formed with lasers in that easy observation is possible, and development of intense terahertz light sources is of great significance for clarification of LIPSS formation mechanisms. Aiming at outperforming laser efficiency achieved by a Chinese research group 11 (laser: 40 mJ, terahertz radiation: 100 µJ), we developed an intense terahertz light source using a high‐energy titanium‐sapphire laser (T6 laser).…”