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.