High-resolution cell imaging using white light phase shifting interferometry and iterative phase deconvolution.

An optimization algorithm is presented for the deconvolution of a complex field to improve the resolution and accuracy of quantitative phase imaging (QPI). A high-resolution phase map can be recovered by solving a constrained optimization problem of deconvolution using a complex gradient operator. The method is demonstrated on phase measurements of samples using a white light based phase shifting interferometry (WLPSI) method.

Label-free high-resolution white light quantitative phase nanoscopy system.

We present a high-resolution white light quantitative phase nanoscopy (WLQPN) system that can be utilized to visualize nanoparticles and subcellular features of the biological specimens. The five-phase shifting technique, along with deconvolution, is adopted to obtain super-resolution in phase imaging. The phase shifting technique can provide full detector resolution, making it beneficial as compared to the well-known Fourier analysis method.

White light phase shifting interferometric microscopy with whole slide imaging for quantitative analysis of biological samples.

In this paper, we demonstrate the white light phase shifting interferometer employed as whole slide scanner and phase profiler for determining qualitative and quantitative information over large field-of-view (FOV). Experiments were performed on human erythrocytes and MG63 Osteosarcoma cells. Here, we have recorded microscopic images and phase shifted white light interferograms simultaneously in a stepped manner.

Development of multimodal micro-endoscopic system with oblique illumination for simultaneous fluorescence imaging and spectroscopy of oral cancer.

Multimodality of an optical system implies the use of one or more optical techniques to improve the system's overall performance and maximum utility. In this article, we demonstrate a multimodal system with oblique illumination that combines two different techniques; fluorescence micro-endoscopy and spectroscopy simultaneously and can be utilized to obtain diverse information from the same location of biological sample. In present system, use of graded index (GRIN) rod-lens makes it highly compact and oblique incidence decouples illumination geometry with collection geometry, preventing CCD cameras from saturation and reduces number of optical elements, thereby making system further miniaturized and field-portable.

Multimodal biomicroscopic system for the characterization of cells with high spatial phase sensitivity and sub-pixel accuracy.

Multimodal analysis is highly advantageous for various biomedical applications including cancer and brain studies. Simultaneous measurement of quantitative phase with sub-pixel accuracy and fluorescence image is difficult to achieve in single measurement. Conventionally, off-axis interferograms are analyzed using the Fourier-transform method which limits the accuracy of the phase maps by pixel size, and usually the location of the carrier peak is in sub-pixel.

Simultaneous fluorescence and quantitative phase imaging of MG63 osteosarcoma cells to monitor morphological changes with time using partially spatially coherent light source.

Quantitative phase imaging (QPI) technique is used to determine various biophysical parameters, such as refractive index, cell thickness, morphology, etc. On the other hand, fluorescence microscopy is used to acquire information regarding molecular specificity of the biological cells and tissues. Conventionally, a fully coherent light source such as laser is used in QPI technique to obtain the interference fringes with ease; however, its high coherence is also responsible for the generation of speckle and spurious fringes, which results in degraded image quality and affects the phase measurement results too.