How you get two sources to get interference fringes in air wedge?

To create interference fringes in an air wedge, you need two coherent light sources, typically a monochromatic light source like a laser. The air wedge is formed by placing two glass plates at a slight angle, creating a thin air gap that varies in thickness. The light from the coherent sources reflects off the top and bottom surfaces of the air wedge, leading to constructive and destructive interference, which produces observable fringes. These fringes can be analyzed to determine the wavelength of the light or the wedge's angle.