Abstract-Experimental Estimate of the Nonlinear Refractive Index of Crystalline ZnSe in the Terahertz Spectral Range

A. N. Tcypkin, S. E. Putilin, M. C. Kulya, M. V. Melnik, A. A. Drozdov, V. G. Bespalov, X.-C. Zhang, R. W. Boyd, S. A. Kozlov

https://link.springer.com/article/10.3103%2FS1062873818120237


A modification of the Z-scan technique for measuring nonlinear refractive index n2 in the terahertz spectral region is proposed. Measurements are made at a broadband terahertz radiation intensity of 0.8 × 109 W cm−2. Coefficient n2 = 2.5 × 10−11 cm2 W−1 is estimated for semiconductor crystalline ZnSe.

Abstract-Concentration dependence of terahertz generation in jets of water and ethanol mixtures

A. N. Tcypkin, E. A Ponomareva, S. E. Putilin, S. V. Smirnov, S. A. Shtumpf, M. V. Melnik, Y. E, S. A. Kozlov, X.-C. Zhang,

https://www.spiedigitallibrary.org/conference-proceedings-of-spie/10826/1082603/Concentration-dependence-of-terahertz-generation-in-jets-of-water-and/10.1117/12.2501217.short

In this work, we considered mixtures of ethanol and water in the form of jets as samples for THz generation based on laser-induced filamentation. The dependence of the output energy of terahertz radiation on the concentration of ethanol in water was experimentally studied. It is shown that the energy grows linearly, which can be explained by an increase in the ionization energy due to the linear replacement of low-efficient charge carriers (water) with highly-efficient (ethanol). The dependence of the THz generation on the optical angle of incidence on the mixture jets was also demonstrated. The results of this study can be further used to create universal source of terahertz radiation.

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Abstract-Measurement of the nonlinear refractive index in ZnSe crystal by modified methodof Z-scan in the terahertz spectral range

 A. N. Tcypkin,  S. E. Putilin,   M. S. Kulya,  M. Siddiqui, S. Choudhary,  J. Zhao,   V. G. Bespalov, R.W. Boyd,   X. C. Zhang,  S. A. Kozlov

http://ieeexplore.ieee.org/document/8066912/

We report the measurement of the intensity-dependent refractive index m of ZnSe crystal at THz frequencies. We used a modified Z-scan method with an intense THz beam of maximum intensity 0.8×109W/cm2. We measured an extremely large m value of the order of 10−11 cm2/W, which is significantly larger than the m value of ZnSe in the near infrared.