Detecting the Extremely Small Angle of an Axicon by Phase-Shifting Digital Holography

Abstract

Axicon is an optical element that can be used to produce high-quality Bessel beams efficiently. In general, the smaller the base angle of the axicon is, the longer the diffraction-free distance of the generated Bessel beam will be. Therefore, axicon with an extremely small base angle is important for the generation of Bessel beam. However, the measurement of an extremely small base angle is a challenge. Here, we applied the phase-shifting digital holography in the measurement of axicon angle. The errors of the three measured axicons with base angles of 0.5°, 1°, and 1° were 1.94%, 4.43%, and 1.63%, respectively.

Half-pixel sliding window processing for fourfold resolution improvement on single-shot quantitative phase imaging with polarization cameras

“…Quantitative Phase Imaging (QPI) is a label-free technique that can extract local phase shifts proportional to the optical thickness and refractive index of an object , thereby providing a more detailed analysis of phase objects [1]. It can provide information for cell mass calculation [2,3], intracellular transport analysis [4][5][6], blood testing [7][8][9], cancer diagnosis [10,11], defect detection [12][13][14], tissue scattering study [15][16][17], and so on. Among various available QPI techniques, off-axis and on-axis interferometry are most widely used, mainly because of the fact that they only require simple and cost-effective optical elements to realize.…”