Snapshot Phase-Shifting Diffraction Phase Microscope

This invention proposes combining snapshot phase-shifting interferometry with high resolution polarization imaging to create quantitative phase maps from diffraction microscopy. A polarization grating separates the incident beam into object and reference beams, and a digital camera captures four phase-shifted interferograms from polarization filters to reconstruct a high spatial resolution phase map. Due to the common path configuration and snapshot feature, the proposed system provides a feasible way for real time quantitative phase measurement with minimal environmental impact. 

Background:
Quantitative phase imaging (QPI) refers to methods of collecting high resolution images and using both phase and amplitude data to create quantitative phase maps. These are particularly valuable for microscopic examination of tissue samples because data can be collected with minimal harm to the tissue and in some cases may be collected in vivo. Traditional QPI methods require widely separated optical paths, which can introduce noise through vibrations in the setup or even air turbulence. Diffraction phase microscopy and other off-axis imaging systems reduce this noise through using a common optical path for the object and reference beam, but this configuration often limits the size of the imaging field that can be collected. Also, creating the phase maps can be computationally intensive, preventing real-time imaging. Algorithm refinement can reduce the processing time for holographic imaging (another off-axis image collection method), as can optimization of graphics processing.

This invention overcomes these limitations by using a diffraction phase microscope with polarization grating, phase-shifting interferometry, and a polarization camera to create a larger field real-time phase map. Similar approaches use holography with spatial light modulators, diffraction phase microscopy with optimized graphics card processing, polarization wavefront shaping, and digital holography with polarization states.

Applications:

• Quantitative phase microscope
• Real time application
• Life sciences research

Advantages:

• Simple
• Compact
• Low-cost