Abstract-Demonstration of a Tilted-Pulse-Front Pumped Plane-Parallel Slab Terahertz Source

Priyo Syamsul Nugraha, Gergő Krizsán, Csaba Lombosi, László Pálfalvi, György Tóth, GÁbor Almási, József András Fülöp, János Hebling

https://arxiv.org/abs/1808.06122

A new type of tilted-pulse-front pumped terahertz (THz) source has been demonstrated, which is based on a lithium niobate plane-parallel slab with an echelon structure on its input surface. Single-cycle pulses of 1 microjoule energy and 0.30 THz central frequency have been generated with 0.05% efficiency from such a source. One order-of-magnitude increase in efficiency is expected by pumping a cryogenically cooled echelon of increased size and thickness with a Ti:sapphire laser. The use of a plane-parallel nonlinear optical crystal slab enables straightforward scaling to high THz pulse energies and to produce a symmetric THz beam with uniform pulse shape for good focusability and high field strength.

Abstract-Numerical investigation of a scalable setup for efficient terahertz generation using a segmented tilted-pulse-front excitation

László Pálfalvi, György Tóth, Levente Tokodi, Zsuzsanna Márton, József András Fülöp, Gábor Almási, and János Hebling

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-25-24-29560v

A hybrid-type terahertz pulse source is proposed for high energy terahertz pulse generation. It is the combination of the conventional tilted-pulse-front setup and a transmission stair-step echelon-faced nonlinear crystal with a period falling in the hundred-micrometer range. The most important advantage of the setup is the possibility of using plane parallel nonlinear optical crystal for producing good-quality, symmetric terahertz beam. Another advantage of the proposed setup is the significant reduction of imaging errors, which is important in the case of wide pump beams that are used in high energy experiments. A one dimensional model was developed for determining the terahertz generation efficiency, and it was used for quantitative comparison between the proposed new hybrid setup and previously introduced terahertz sources. With lithium niobate nonlinear material, calculations predict an approximately ten-fold increase in the efficiency of the presently described hybrid terahertz pulse source with respect to that of the earlier proposed setup, which utilizes a reflective stair-step echelon and a prism shaped nonlinear optical crystal. By using pump pulses of 50 mJ pulse energy, 500 fs pulse length and 8 mm beam spot radius, approximately 1% conversion efficiency and 0.5 mJ terahertz pulse energy can be reached with the newly proposed setup.

© 2017 Optical Society of America