Real-time phase shift interference microscopy

Abstract

A real-time phase shift interference microscopy system is presented using a polarization-based Linnik interferometer operating with three synchronized, phase-masked, parallel detectors. Using this method, several important applications that require high speed and accuracy, such as dynamic focusing control, tilt measurement, submicrometer roughness measurement, and 3D profiling of fine structures, are demonstrated in 50 volumes per second and with 2 nm height repeatability.

Quadrature wavelength scanning interferometry

“…However, in our setup, the mechanical scanning reintroduced does not affect the measurement speed which is set by the CCD camera frame rate. For high-speed cameras, the mechanical scaning can be completely avoided by capturing two or more phase shifts in a single shot employing multiple cameras [24] or a phase-shifts pixelated mask [23]. However, in the case of a phase-shifts pixelated mask, additional polarisation optics are required and errors might arise from object dependent polarisation effects and the mask's dependency on the wavelength and polarisation of the light.…”

High‐resolution single‐shot phase‐shifting interference microscopy using deep neural network for quantitative phase imaging of biological samples

“…Besides, phase reconstruction of step height larger than half the wavelength of the light cannot be extracted in a single laser-based QPI due to 2π ambiguities [13,14]. To overcome these limitations, white light phase-shifting interference microscopy (WL-PSIM) is the most commonly used technique for ultra-sensitive measurement in both industrial and biological specimens [15][16][17]. WL-PSIM is based on the principle of low coherence interferometry where back-reflected light from the sample and reference arm are superimposed and forms an interference pattern only if the optical path difference (OPD) between these two arms lies within the coherence length (L c ) of the light source, that is, OPD≤ L c .…”

“…Although PSI has the advantage of utilizing the full resolution of the system, requirement of multiple frames is the key obstacle in PSI for many applications such as live-cell imaging and measurement with dynamic samples [22]. To overcome these limitations, various singleshot phase-shifting approaches have been developed in the recent past [13,[23][24][25][26]. However, these approaches either suffer with complex experimental setups while using multiple charge couple device (CCD) cameras or significantly increases the cost of the system [17,23,26].…”

Quantitative Phase Imaging During Cell Division Based on Dual-Channel Microscopic Interferometry System

“…Of all the interferometry methods, the off-axis and spatial domain phase-shifting methods, in which the Fourier transform [23] and Hilbert transform [27] are utilized to perform phase retrieval of measured sample, but the corresponding accuracy is affected by the noise and size of filtering window. To improve the accuracy, Mach-Zehnder interferometry [28], Michelson interference microscopy [29], Linnik interferometry [30] are developed, and the reconstruction accuracy of the phase and amplitude images from the recorded interferograms varies with the hardware configuration. Overall,these technologies have achieved some cellular state characterization parameters, such as dry mass [31], activity [32], intracellular homeostasis exploration and cellular apoptosis and traction measurement [33], [34] with relative high accuracy.…”