Propagation Enhancement Factor in the Spin Hall Effect of Light (SHEL) Observation for Smooth Optics Measurement

Spin Hall Effect of Light (SHEL) is a light interaction that deviates from the classic geometrical optics behavior, rooted from the balance and conservation of angular momentum of light. In the presence of SHEL, a linearly polarized beam incident on a dielectric interface will be reflected as two split beams having different handedness of circular polarizations shifted from their supposed reflection trajectories. The transverse shift of SHEL is known to be subwavelength, therefore one of the extensively used methods is the weak measurement that can amplify the information to make it easier for SHEL observation. By predefining the initial and final state of light in SHEL weak measurement it has shown potential for precision measurement application such as refractive index measurement. Previously, it has been mentioned that the signal amplification in SHEL observation also depends on the effect of beam propagation that contributes an amplification factor due to the propagation nature of gaussian beam. In this paper, the propagation factor is experimentally investigated by observing the utilization of different lens pairs in the SHEL weak measurement setup. Furthermore, the investigation is particularly done to see how it affects the measurement of smooth optics based on SHEL observation.