Determination of refractive indices of layered GaSe by help of wavelength modulation spectroscopy

Abstract

After obtaining graphene, the study of layered materials received a second breath. As with other layered 2D structures like graphene, adjacent GaSe layers are bound by the weak van der Waals force. This makes it possible to peel the structure by mechanical or liquid exfoliation. The resultant ultra-thin few or single layer 2D gallium selenide nanosheets or nanoparticles have well-known nonlinear optical properties and a range of applications in areas including integrated optics, optical information communications and biology. Weak Van der Waals bonds of this material allow obtaining samples of various thicknesses. One of the fundamental optical constants of any material is the dialectical permittivity, and in particular its real part called the refractive index. One of the methods for obtaining this constant is its calculation from the interference fringes at a known sample thickness.