Measurement of the electro-optic coefficient of a BaMgF_4 single crystal

Abstract

BaMgF4 single crystal is a promising candidate for many applications in the vacuum ultraviolet region. The electro-optic coefficient of BaMgF4 single crystal is measured by means of a symmetric metal-cladding waveguide, in which the effect refractive index is very sensitive to the change of the refractive index of the guiding layer. The resonance excitation angle shifts as the applied electric filed on the waveguide changes. Subsequently, the electro-optic coefficient γ13 = −36.2 pm/V of BaMgF4 single crystal is determined by measuring the variations of effective refractive index of the waveguide with different applied voltages. This considerable EO coefficient |γ13| is even larger than the largest one of LiNbO3 (γ51 = 32.6 pm/V) which offers an opportunity for the fabrication of vacuum ultraviolet electro-optic modulators and optical switches by BaMgF4 single crystal.