White light lateral shear interferometer with holographic shear lenses and spatial Fourier transform.

Lateral shear interferometer is a simple yet powerful method for testing wavefronts or measuring refractive index changes. Previously, we have reported a method of using two holographic lenses to obtain shear and to generate a spatial frequency carrier, which was used for quantitative analysis. This technique has some advantages such as stability and instantaneous measurements. In this Letter, we report a method of using white light with holographic gratings to obtain shear and also to perform wavefront analysis using the spatial carrier fringes generated at a specific selected wavelength from the white light spectrum. We show that the sensitivity of the setup can be changed by selecting different wavelengths from the spectrum.