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Book ChapterDOI

Differential Phase Imaging of Evanescent Wave in Total Internal Reflection for Determining Refractive Index

TL;DR: In this paper, a non-interferometric differential phase measuring technique is used to determine the refractive index of a medium, where the phase change is a function of refractive indices of a pair of media involved.
Abstract: A non-interferometric differential phase measuring technique is used to determine the refractive index of a medium. In total internal reflection (TIR), phase change is a function of the refractive indices of a pair of media involved. Also, the said phase change is different for p-polarized and s-polarized light components. Difference between the phases of these two polarized light components leads to the refractive index of the sample. The theory of the technique is discussed and a simple experimental method is demonstrated to determine the phase difference of the totally internally reflected p and s components.
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Journal ArticleDOI
TL;DR: The phase shift of cells from type L 929 fibroblast and mitochondria from liver cells was measured and the Fraunhofer diffraction of the measured phase object is calculated.
Abstract: With a phase microscope the phase shift of cells from type L 929 fibroblast and mitochondria from liver cells was measured. Compared to the total phase shift caused by the cell relative to vacuum (approximately 1400 nm) the single phase shift of the mitochondria (approximately 180 nm) is small. Only the nucleus and the membrane of the cell give a visibly different phase shift relative to the mean value of the cell. The Fraunhofer diffraction of the measured phase object is calculated. With a simplified scattering theory, i.e. Rayleigh - Gans scattering, different phase objects are investigated and their differential cross section is discussed.

342 citations

Journal ArticleDOI
TL;DR: An accurate and efficient method for measuring the refractive indices of a transparent plate by analyzing the transmitted intensity versus angle of incidence and independent determination of the absolute index of refraction and the thickness with a relative uncertainty of 10(-5).
Abstract: We developed an accurate and efficient method for measuring the refractive indices of a transparent plate by analyzing the transmitted intensity versus angle of incidence. By using two different wavelengths, we resolved the 2pi-ambiguity inherent to the phase measurement involving a thick medium, leading to independent determination of the absolute index of refraction and the thickness with a relative uncertainty of 10(-5). The validity and the accuracy of our method were confirmed with a standard reference material. Furthermore, our method is insensitive to environmental perturbations, and simple to implement, compared to the conventional index measurement methods providing similar accuracy.

67 citations

Journal ArticleDOI
28 Aug 2014-Sensors
TL;DR: This work discusses the advancements in interferometric SPR methods to measure the phase shifts due to refractive index changes, and solutions are suggested to enhance the performance parameters that will aid in future biological and chemical sensors.
Abstract: Surface plasmon resonance (SPR) is a novel optical sensing technique with a unique ability to monitor molecular binding in real-time for biological and chemical sensor applications. Interferometry is an excellent tool for accurate measurement of SPR changes, the measurement and comparison is made for the sensitivity, dynamic range and resolution of the different analytes using interferometry techniques. SPR interferometry can also employ phase detection in addition to the amplitude of the reflected light wave, and the phase changes more rapidly compared with other approaches, i.e., intensity, angle and wavelength. Therefore, the SPR phase interferometer offers the advantages of spatial phase resolution and high sensitivity. This work discusses the advancements in interferometric SPR methods to measure the phase shifts due to refractive index changes. The main application areas of SPR sensors are demonstrated, i.e., the Fabry-Perot interferometer, Michelson interferometer and Mach-Zehnder interferometer, with different configurations. The three interferometers are discussed in detail, and solutions are suggested to enhance the performance parameters that will aid in future biological and chemical sensors.

62 citations

Journal ArticleDOI
TL;DR: This work introduces a new microscopy technique termed total internal reflection holographic microscopy (TIRHM), which uses quantitative phase microscopy by digital holography to image the phase profile of light in totalinternal reflection, which is modulated by the materials present on or near the surface of internal reflection.
Abstract: We introduce a new microscopy technique termed total internal reflection holographic microscopy (TIRHM). Quantitative phase microscopy by digital holography is used to image the phase profile of light in total internal reflection, which is modulated by the materials present on or near the surface of internal reflection. The imaging characteristics are theoretically modeled and imaging capabilities are experimentally demonstrated.

55 citations

Journal ArticleDOI
TL;DR: The concept of phase-sensitive Si-based Total Internal Reflection bio- and chemical sensor using the reflection of light from an internal edge of a Si prism, which is in contact with analyte material changing its index of refraction, leads to a high sensitivity and dynamic range of measurements.
Abstract: A concept of phase-sensitive Si-based Total Internal Reflection bio- and chemical sensor is presented. The sensor uses the reflection of light from an internal edge of a Si prism, which is in contact with analyte material changing its index of refraction (thickness). Changes of the refractive index are monitored by measuring the differential phase shift between p- and s-polarized components of light reflected from the system. We show that due to a high refractive index of Si, such methodology leads to a high sensitivity and dynamic range of measurements. Furthermore, the Si-based platform offers an easy bioimmobilization step and excellent opportunities for the development of multi-channel microsensors taking advantage of the advanced state of development of Si-based microfabrication technologies.

24 citations