The double-slit experiment performed by Thomas Young over two-hundred years ago established that light has wavelike properties. Since then, methods derived from double-slit experiment have become fundamental to numerous precision measurements.

Textbook understanding of the double-slit experiment has evolved upon analyzing the wave interference associated with symmetric double-slit. Symmetric double-slit refers to the two slits being identical in terms of their physical dimensions (size and shift from the optical axis) and properties (color) of light passing them. A practical configuration of double-slit will, however, never be exactly symmetric between the two slits. And interpreting the interference patterns associated with asymmetric double-slit by assuming symmetric double-slit may bring in systematic error affecting the precision of measurement that double-slit has to offer.

The objective of this research is to theoretically understand how and to what extent the slit-asymmetry affects the wave-interference of double-slit. The theoretical analysis is based on implementing slit-asymmetry into the Fresnel-Fraunhofer treatment of light standard to modeling double-slit interference. The Fresnel-Fraunhofer treatment calculates the complex electrical field of light on an observing plan as the superposition of the light filed originating from the two slits. By adjusting the asymmetry of the complex electrical fields originating from the two slits, it is possible to analytically predict the resulted double-slit interference for comparing against existing results of numerical simulations [Piao, 2022]. Two types of slit-asymmetries will be considered: asymmetry of the geometric dimensions and asymmetry of the light properties. Starting with ideal double-slit, the effect of slit-asymmetry will be analyzed type-by-type.