A hydrogen-bonded organic nonlinear optical crystal for high-efficiency terahertz generation and detection

ETH Zurich, Institute of Quantum Electronics, Nonlinear Optics Laboratory, 8093 Zurich,Switzerland.
Optics Express (Impact Factor: 3.53). 11/2008; 16(21):16496-508. DOI: 10.1364/OE.16.016496
Source: PubMed

ABSTRACT Broadband THz pulses have been generated in 2-[3-(4- hydroxystyryl)-5,5-dimethylcyclohex-2-enylidene]malononitrile (OH1) by optical rectification of sub-picosecond laser pulses. We show that OH1 crystals allow velocity-matched generation and detection of THz frequencies in the whole range between 0.3 and 2.5 THz for a pump laser wavelength range from 1200 to 1460 nm. OH1 crystals show a higher figure of merit for THz generation and detection in the optimized range compared to the benchmark inorganic semiconductor crystals ZnTe and GaAs and the organic ionic salt crystal 4-N,N-dimethylamino-4'-N'-methyl stilbazolium tosylate (DAST). The material shows a low THz absorption coefficient alpha3 in the range between 0.3 and 2.5 THz, reaching values lower than 0.2mm(-1) between 0.7 and 1.0 THz. This is similar as in ZnTe and GaAs, but much lower than in DAST in the respective optimum frequency range. A peak THz electric field of 100 kV/cm and a photon conversion efficiency of 11 percent have been achieved at a pump pulse energy of 45 microJ.

Download full-text


Available from: Arno Schneider, Jun 24, 2015
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The brightness of a light source defines its applicability to nonlinear phenomena in science. Bright low frequency terahertz (< 5THz) radiation confined to a diffraction-limited spot size is a present hurdle due to the broad bandwidth and long wavelengths associated with single-cycle terahertz pulses as well as due to the lack of terahertz wavefront correctors. Here, using a present-technology system, we employ a new concept of terahertz wavefront manipulation and focusing optimization. We demonstrate a spatio-temporal confinement of terahertz energy at its physical limits to the least possible 3-dimensional light bullet volume of lambda cubic. This leads to a new regime of extremely bright terahertz radiation reaching 40 PW/m2 intensity. The presented work is focused on the sub-5 THz range using small aperture organic crystals DSTMS and OH1. The obtained peak field of up to 5 GV/m and 17 Tesla is order of magnitude higher than any reported single-cycle field oscillation in the entire THz range from a laser-based system and surpassing large scale accelerator systems. The presented results are foreseen to have a great impact on future nonlinear terahertz applications in different science disciplines.
  • [Show abstract] [Hide abstract]
    ABSTRACT: We demonstrate co-crystallization of analogous phenolic polyene molecules that form non-isomorphic single-component crystal structures for nonlinear optical applications. The analogous polyene molecules form similar main supramolecular hydrogen-bond interactions with neighboring molecules resulting in polar linear molecular chains, but form different crystal space groups in single component crystals, which have a different orientation of these molecular chains due to subtle variations of weak intermolecular interactions. The resulting co-crystal structure is isomorphous with one of the single-component crystals. In co-crystallization with competition between two analogous crystal structures, the solubility plays an important role to select the equilibrium crystal structure of co-crystals. The phenolic polyene co-crystals retain optimal molecular ordering with large macroscopic nonlinearity of single component crystals for nonlinear optical applications.
    CrystEngComm 06/2012; 14(13):4306-4311. DOI:10.1039/C2CE06057D · 3.86 Impact Factor
  • Source
    Journal of the Optical Society of America B 06/2015; 32(6):1078. DOI:10.1364/JOSAB.32.001078 · 1.81 Impact Factor