Breakthroughs in Photonics 2013: Quantitative Phase Imaging: Metrology Meets Biology

Abstract

Quantitative phase imaging (QPI) is an emerging optical approach that measures the optical path length of a transparent specimen noninvasively. Therefore, it is suitable for studying unstained biological tissues and cells with high sensitivity and resolution. This capability of QPI has fueled itself to grow rapidly as an active field of study for the past two decades. With this trend, QPI has experienced some breakthroughs in methods and applications in the past year. We briefly review some of these breakthroughs in method, including QPI through silicon marker-free phase nanoscopy and white-light diffraction tomography. Furthermore, some of the applications, such as quantitative phase measurement of cell growth and real-time blood testing, are introduced to show the importance and applicability of the field.

Methods for cell volume measurement

“…There are some methods whose primary purpose may be different from measuring the cell volume but where the volume may come as an attendant result. The term “quantitative phase imaging” refers to a group of techniques that quantify the delay of a light wave passing through a sample . The phase delay Δ φ introduced by a cell is typically measured relative to that in the cell‐free area; thus, Δ φ is proportional both to cell thickness h and to the refractive index difference between the cell and surrounding liquid: …”

Solving inverse scattering problems in biological samples by quantitative phase imaging

“…Over the past decade, QPI has been recognized as an emerging area of research, as it enables previously inaccessible biological applications: cell dynamics , cell growth , blood testing , molecular detection cell cytoplasm flow , heart cell beating , neuron imaging , monitoring electric activity in nerves , cell and tissue refractometry , cell rheology and, more recently, tomographic cell imaging . Reference reviews several major QPI technology breakthroughs in 2013.…”

“…Building upon these experimental results, Kim et al. have developed a physical model to describe the 3D imaging principle of SLIM system, by extending Emil Wolf's diffraction tomography to a broad‐band source, and further improved the tomographic imaging using SLIM . This result is described in detail in Section .…”

Higher Order Transport of Intensity Equation Methods: Comparisons and Their Hybrid Application for Noise Adaptive Phase Imaging

“…Compared to the often used bright/dark field and fluorescent microscopy, quantitative phase microscopy provides a new way for cell and tissue observations. It is able to realize high-contrast imaging without sample staining [1], [2], additionally, the retrieved phase can be adopted for sample detail analysis such as measuring optical thickness and distinguishing sample configurations [3].Therefore, various methods have been proposed to extract quantitative sample phase distributions. Ptychography including spatial domain based ptychographic iterative engine [4], [5] and frequency domain based Fourier ptychographic microscopy [6]- [8] can realize quantitative phase imaging often with extremely large field of view (FoV) and high resolution.…”