Edge-Enhanced Microscopy of Comlplex Object using Scalar and Vectorial Vortex Filtering

TL;DR

This paper investigates scalar and vectorial vortex filtering in a $4f$ system for edge detection of phase-amplitude objects, proposing a method to isolate phase edges and validating results through experiments and simulations.

Contribution

It provides a comparative analysis of scalar and vectorial vortex filtering and introduces a novel off-axis illumination technique to isolate phase object edges.

Findings

Vectorial vortex filtering enhances edges of phase and amplitude objects.

Edges of phase and amplitude objects are indistinguishable with vectorial filtering.

Off-axis illumination effectively isolates phase object edges.

Abstract

Recently, $4f$ system containing a q-plate has been used to perform edge detection and enhancement of amplitude and phase objects. However, only few studies have concentrated on edge enhancement of phase-amplitude objects. Here, we experimentally verified the functional difference between scalar and vectorial vortex filtering using an onion cell, the experimental results agree well with theoretical analysis. We verified our experimental results through numerical simulation. Although vectorial vortex filtering successfully enhanced the edges of phase and amplitude objects in the phase-amplitude object, they are indistinguishable due to the equal enhancement of the edges of the phase and amplitude objects. To address this, we propose a method to isolate the edge of the phase object from the edge of the amplitude object using off-axis beam illumination. We theoretically calculated the isolation of the edge of the phase object from the amplitude object, and verified via numerical simulations.