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Light's internal reflectivity near a critical angle is very sensitive to the angle of incidence and the optical properties of the external medium near the interface. Novel applications in biology and medicine of subcritical internal…

We propose the use of an optically trapped, dye doped polystyrene microsphere for spatial probing of the refractive index at any position in a fluid. We demonstrate the use of the dye embedded in the microsphere as an internal broadband…

Optics · Physics 2015-06-26 P. Zijlstra , K. L. van der Molen , A. P. Mosk

For the investigation of two-component aerosols one needs to know the refractive indices of the two aerosol components. One problem is that they depend on temparature and pressure, so one needs for their determination a robust measurement…

Numerical Analysis · Mathematics 2016-12-20 Tobias Kyrion

Dynamic thin film interferometry is a technique used to non-invasively characterize the thickness of thin liquid films. Recovering the underlying thickness from the captured interferograms, unconditionally and automatically is still an open…

Photon transport through a diffusing slab can be described by the radiative transfer equation (RTE). When the slab is highly scattering and weakly absorbing, the RTE simplifies to the diffusion equation. In this paper, an inverse diffusion…

Two approaches (micro- and macro- investigations) are used to determine the dimension dependences of the optical parameters of the nanometer-scale layers of materials. It is shown that both an index of refraction and coefficient of…

Materials Science · Physics 2016-10-13 T. A. Kudykina , A. I. Pervak

We present a simple but effective method to extract the reflectivity spectra from the interference signals with a large NA white light interferometry. Numerical simulations and experiments have demonstrated the effectiveness of our method.…

Optics · Physics 2025-03-11 Cheng Chen , Lixuan Xu , Rong Su

We present a five level atomic system in which the index of refraction of a probe laser can be enhanced or reduced below unity with vanishing absorption in the region between pairs of absorption and gain lines formed by dressing of the…

Quantum Physics · Physics 2011-03-17 Steven A. Sagona-Stophel , James Owen Weatherall , Christopher P. Search

PASCO scientific 012-05187C Precision Interferometer is used in Michelson mode to investigate wavelengths and refractive indices. From varying the distance of the movable mirror in the Michelson setup the wavelength of the HeNe laser beam…

Instrumentation and Detectors · Physics 2020-01-08 Kamyar Modjtahedzadeh

A modified weak measurement scheme, rotatory biased weak measurement, is proposed to significantly improve the sensitivity and resolution of the refractive index sensor on a total reflection structure. This method introduces an additional…

Quantum Physics · Physics 2022-04-25 Chongqi Zhou , Yang Xu , Xiaonan Zhang , Zhangyan Li , Tian Guan , Yonghong He , Yanhong Ji

Many adaptive optics systems operate by measuring the distortion of the wavefront in one wavelength range and performing the scientific observations in a second, different wavelength range. One common technique is to measure wavefront…

Astrophysics · Physics 2009-11-07 Henry G. Roe

Future laser-interferometric gravitational wave detectors (GWDs) will potentially employ test mass mirrors from crystalline silicon and a laser wavelength of $1550\,\rm{nm}$, which corresponds to a photon energy below the silicon bandgap.…

Long cylinders, such as optical fibers, are some of the most widely used photonic devices. The radius and refractive index of these fibers are therefore fundamentally important parameters in determining their performance. We have developed…

Optics · Physics 2022-07-20 Mathieu Couillard , Pablo Bianucci

Poly(methyl methacrylate), PMMA, is a popular polymer for optical applications due to its superior transmission and reflection. However, its optical properties in the ultraviolet regime still need to be thoroughly studied. Using the…

Optics · Physics 2023-11-01 Pham Thi Hong , Hung Q. Nguyen , H. T. M. Nghiem

We present a practical white-light interferometric method, supported by an open-source Python library \textit{optifik} for automated spectrum-to-thickness deduction, enabling foam film measurements down to a few nanometers. We describe…

In this work, a refractive index (RI) sensor with an effective integration of colorimetric detection and optical sensing capabilities has been developed. Colorimetric detection relies on the sensitivity of the structural color of photonic…

Optics · Physics 2021-07-09 Cheng Fang , Qingqing Shang , Fen Tang , Songlin Yang , Ran Ye

Reflectometry is a technique that uses the light reflected by a sample to determine properties of the sample. Interferometric reflectometry uses interference between two beams, one of which is incident on ---and reflected back by--- a…

Optics · Physics 2019-10-10 Alexander Nahmad-Rohen , Wolfgang Langbein

Reliable control of the deposition process of optical films and coatings frequently requires monitoring of the refractive index profile throughout the layer. In the present work a simple in situ approach is proposed which uses a WKBJ matrix…

Optics · Physics 2009-10-31 Daniel Poitras , Ludvik Martinu

A refractometry taking measuring of Brewster angles for birefringent materials is proposed. The technique is based on the angular scanning of the reflected power of p-polarized light and the determination of the two specific minimums at the…

General Physics · Physics 2019-08-27 E. A. Tikhonov , A. K. Lyamets

For a number of optical applications, it is advantageous to precisely tune the refractive index of a liquid. Here, we harness a well-established concept in optics for this purpose. The Kramers-Kronig relation provides physical connection…