When a parallel beam of light illuminates an aperture, the uncertainty principles require associating probability amplitude to a photon at each point of the aperture. Superposition of the amplitudes at the observation point behind the aperture, determines the probability that the photon strikes the point. In this report, we show that this “photon approach” explains several optical concepts. The approach is applied to study the diffraction from a single slit, double slit, and transmission phase step. Then, we apply it to explain the diffraction from a bi-prism and a Michelson’s interferometer, and show that the photon approach to the appearance of the interference fringes is more reasonable than the wave approach. We deduce the coherence behavior of light from the uncertainty principles, and finally, we use the photon approach to extract the ray optics laws and image formation formulae.

Optical diffractometry (OD) using a phase step is an elegant alternative for interferometry, further, has least sensitivity to environmental vibrations. Therefore, OD has found numerous interesting metrological and technological applications. OD utilizes a phase step to detect the influence of objects under measurement by the changes in the Fresnel diffraction pattern. Recently, we showed that such measurements do not require infinitively sharp phase steps, although fabrication of such sharp elements is also impossible [1]. Here, we address the issue of smoothness of the phase step surfaces. So far, in all of the OD applications the surfaces of the incorporated phase steps are considered to be optically smooth and flat. However, practically, some amount of roughness and unflatness is unavoidable even in precise and careful fabrication process. We show that preserving the OD-diffraction-pattern characteristics of a phase step depends on the level of roughness in the surfaces of the phase step. We define number of detectable fringes and autocorrelation functions of the diffraction patterns as the measures for evaluating the similarity of the rough phase step diffractions to the ideal case. We derive the theoretical description and confirm the results with simulations and experiments.

Optical diffractometry (OD) using a phase step is an elegant alternative for interferometry, further, has least sensitivity to environmental vibrations. Therefore, OD has found numerous interesting metrological and technological applications. OD utilizes a phase step to detect the influence of objects under measurement by the changes in the Fresnel diffraction pattern. Recently, we showed that such measurements do not require infinitively sharp phase steps, although fabrication of such sharp elements is also impossible [1]. Here, we address the issue of smoothness of the phase step surfaces. So far, in all of the OD applications the surfaces of the incorporated phase steps are considered to be optically smooth and flat. However, practically, some amount of roughness and unflatness is unavoidable even in precise and careful fabrication process. We show that preserving the OD-diffraction-pattern characteristics of a phase step depends on the level of roughness in the surfaces of the phase step. We define number of detectable fringes and autocorrelation functions of the diffraction patterns as the measures for evaluating the similarity of the rough phase step diffractions to the ideal case. We derive the theoretical description and confirm the results with simulations and experiments.

When a parallel beam of light illuminates an aperture, the uncertainty principles require associating probability amplitude to a photon at each point of the aperture. Superposition of the amplitudes at the observation point behind the aperture, determines the probability that the photon strikes the point. In this report, we show that this “photon approach” explains several optical concepts. The approach is applied to study the diffraction from a single slit, double slit, and transmission phase step. Then, we apply it to explain the diffraction from a bi-prism and a Michelson’s interferometer, and show that the photon approach to the appearance of the interference fringes is more reasonable than the wave approach. We deduce the coherence behavior of light from the uncertainty principles, and finally, we use the photon approach to extract the ray optics laws and image formation formulae.

When a parallel beam of light illuminates an aperture, the uncertainty principles require associating probability amplitude to a photon at each point of the aperture. Superposition of the amplitudes at the observation point behind the aperture, determines the probability that the photon strikes the point. In this paper, we show that this “photon approach” explains several optical concepts. The approach is applied to study the diffraction from a single slit, double slit, and transmission phase step. Then, we apply it to explain the diffraction from a bi-prism and a Michelson’s interferometer, and show that the photon approach to the appearance of the interference fringes is more reasonable than the wave approach. We deduce the coherence behavior of light from the uncertainty principles, and finally, we use the photon approach to extract the ray optics laws and image formation formulae.