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Abstract There is a significant gap in cost-effective quantitative phase microscopy (QPM) systems for studying dynamic cellular processes while maintaining accuracy for long-term cellular monitoring. Current QPM systems often rely on complex and expensive voltage-controllable components like Spatial Light Modulators or two-beam interferometry. To address this, we introduce a QPM system optimized for time-varying phase samples using azobenzene liquid crystal as a Zernike filter with a polarization-sensing camera. This system operates without input voltage or moving components, reducing complexity and cost. Optimized for gentle illumination to minimize phototoxicity, it achieves a 1 Hz frame rate for prolonged monitoring. The system demonstrated accuracy with a maximum standard deviation of ±42 nm and low noise fluctuations of ±2.5 nm. Designed for simplicity and single-shot operations, our QPM system is efficient, robust, and precisely calibrated for reliable measurements. Using inexpensive optical components, it offers an economical solution for long-term, noninvasive biological monitoring and research applications. 

This study showcases the multifunctionality of a single-shot quantitative phase microscopy (QPM) system for comprehensive cell analysis. The system captures four high-contrast images in one shot, enabling tasks like cell segmentation, measuring cell confluence, and estimating cell mass. We demonstrate the usability of the QPM system in routine biological workflows, showing how its integration with computational algorithms enables automated, precise analysis, achieving accuracy scores between 85% and 97% across samples with varying cell densities, even those with low signal-to-noise ratios. This cost-effective tool operates under low-intensity light and resists vibrations, making it highly versatile for researchers in both optical and biological fields. 

We report the implementation of an interferometric null test using a high-definition spatial light modulator (SLM) as a reconfigurable alternative to a computer-generated hologram. We detail the alignment process chain, including novel techniques using the SLM to project alignment fiducials on the test part. To validate the alignment protocol, we measure a mild off-axis conic with the SLM-based system and cross-validate with conventional interferometry within 30 nm root-mean-square (RMS) surface figure. Finally, we report the null test of a 65 mm clear aperture concave freeform with 91 μm peak-valley sag departure from the base sphere. The measured surface figure of the freeform is within 40 nm RMS compared to the measurement with a commercial metrology instrument. 

Optical vortices are widely used in optics and photonics, impacting the measurements and conclusions derived from their use. Thus, it is crucial to evaluate optical vortices efficiently. This work aims to establish metrics for evaluating optical vortex quality to support the implementation procedure and, hence, provide a tool supporting research purposes and technological developments. We propose to assess vortex quality using the following intensity parameters: eccentricity, cross-sectional peak-to-valley, cross-sectional peak difference, and the doughnut ratio. This methodology provides a low-cost, robust, and quantitative approach to evaluating optical vortices for each specific optical technology. 

This work presents a stable noise-robust numerical integration technique derived from a gradient representation of the Q-Forbes polynomials for surfaces with axial symmetry. This modal-integration technique uses an orthogonalization process through the Householder reflections to obtain a numerically orthogonal set for the surface slopes that is used to reconstruct the surface shape. It is shown that for typical Deflectometry measurements, the resulting random component of the uncertainty after numerical integration has a root mean square error well below 1nm. 

A super-sensitive phase measuring Deflectometry technique is presented to obtain effective fringe periods beyond the MTF limit. This allows decreasing significantly the random component of the uncertainty in the measured slope.