Refractive index modulation induced by high intensity THz radiation

Non-collinear electro-optic detection scheme is employed to estimate the nonlinear refractive index and absorption coefficient of silicon and lactose in the terahertz (THz) spectral regime extending from 0.1 to 3 THz. The highest THz field strength of the THz pulse was 440 MV/m. The results are also compared with that obtained from z-scan method. The maximum observed change in the refractive index (Δn) was -0.128 and + 0.245 for lactose and silicon samples respectively.