Optical scanning holography with a polarization directed flat lens

Abstract

Recently, an optical scanning holographic system with a polarization directed flat lens was proposed to realize coaxial scanning holography (CSH). The advantage of CSH is its small form factor and the stability. However, the diffraction efficiency of the polarization directed flat lens cannot be 100%, and thus there is always zeroth order light in the scanning beam. The imperfect diffraction property of the polarization directed flat lens results in an incomplete scanning Fresnel zone plate. Consequently, the reconstructed image is blurred and noisy. In this paper, we compared different methods, including the back propagation, the phase correlation, and inverse filtering, for the hologram reconstruction. It is demonstrated that inverse filtering is the only method that can retrieve the high-frequency component of the hologram. However, additional noise also arises with the use of inverse filtering. Therefore, the imaging performance of CSH by using a polarization directed flat lens is inherently worse than that of conventional OSH.

Off-axis optical scanning holography [Invited]

“…Figure 8(c) is the incoherent hologram calculated by Eq. ( 16) and its magnitude spectrum is 17) and (18), respectively, of the incoherent hologram. Interestingly, the reconstructed images are edge-enhanced, and this can be explained as follows.…”

“…Instead of heterodyning, homodyning also has been employed in OSH [16]. Since the standard optical system of OSH employs an interferometric approach for either heterodyning or homodyning, recent efforts have been proposed to partially solve the environmentally sensitive aspect of the use of an interferometer during data acquisition [17,18]. In addition, to reduce the complexity of the optical system, electronic scanning instead of physical optical scanning has been investigated [19,20].…”

Computational Optical Scanning Holography

“…To partially address these challenges, a method using a geometric phase lens was proposed [43,44]. This method employs lenses that change the curvature of outgoing waves based on the circular polarization of the incident light, enabling the realization of FZP in a single optical path.…”