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Control of optical properties of materials by tuning their refractive index can revolutionize the current state-of-the-art technology to manipulate light propagation in the high loss media. Here we demonstrate active optical tuning of the…

Optics · Physics 2025-06-25 Elif Ozturk , Hira Asif , Mehmet Gunay , Mehmet Emre Tasgin , Ramazan Sahin

We have experimentally studied the optical refractive index of few-layer graphene through reflection spectroscopy at visible wavelengths. A laser scanning microscope (LSM) with a coherent supercontinuum laser source measured the…

Mesoscale and Nanoscale Physics · Physics 2016-09-30 Behnood G. Ghamsari , Jacob Tosado , Mahito Yamamoto , Michael S. Fuhrer , Steven M. Anlage

Optical fibers typically confine light through total internal reflection or through photonic bandgaps. Here we show that light can be perfectly guided in optical fibers through a different mechanism based on bound states in the continuum…

Optics · Physics 2020-02-18 Xingwei Gao , Bo Zhen , Marin Soljačić , Hongsheng Chen , Chia Wei Hsu

We present an experimental method to determine the refractive index of $Al_{x}Ga_{1-x}As$ (x = 0.0 - 0.5) from 300 K to 4 K across the 500 - 1100 nm wavelength range. The values are extracted from spectroscopically observed microcavity…

Hollow core antiresonant fibers offer new possibilities in the near infrared and visible spectral range. I show here that the great flexibility of this technology can allow the design and fabrication of hollow core optical fibers with an…

Optics · Physics 2015-09-16 Walter Belardi

Parity-time (PT) symmetric optical sensors operating around exceptional points have recently gained much attraction, offering an unparalleled high sensitivity in measuring small perturbations. In the past, most of the PT-symmetric sensors…

Optics · Physics 2022-08-16 Faiza Iftikhar , Raja Ahmad , M. Imran Cheema

On-chip measurement of thermo-optic coefficient (TOC) of samples along with on-chip temperature measurements can be used to compensate for thermal fluctuation induced noise in refractometry using integrated photonic sensors. In this article…

Instrumentation and Detectors · Physics 2017-10-11 Prashanth R Prasad , Shankar K Selvaraja , Manoj Varma

A resonant photoacoustic cell capable of detecting the traces of gases at an amplitude-modulation regime is represented. The cell is designed so as to minimize the window background for the cell operation at a selected acoustic resonance. A…

Optics · Physics 2014-05-29 A. L. Ulasevich , A. V. Gorelik , A. A. Kouzmouk , V. S. Starovoitov

A high speed quasi-distributed demodulation method based on the microwave photonics and the chromatic dispersion effect is designed and implemented for weak fiber Bragg gratings (FBGs). Due to the effect of dispersion compensation fiber…

Instrumentation and Detectors · Physics 2018-07-04 Lei Zhou , ZhengYing Li , Na Xiang

The absorption spectra of the cold Na2 molecule dressed by a linearly polarized standing laser wave is investigated. In the studied scenario the rotational motion of the molecules is frozen while the vibrational and translational degrees of…

Chemical Physics · Physics 2020-03-18 Mariusz Pawlak , Tamás Szidarovszky , Gábor J. Halász , Ágnes Vibók

The reflectivity of various Bragg reflectors in connection to waveguide structures, including nanowires, has been investigated using modal reflection and transmission matrices. A semi-analytical model was applied yielding increased…

Optics · Physics 2012-06-25 Guro Kristin Svendsen , Helge Weman , Johannes Skaar

Optical fiber multi parameter sensing is fundamentally constrained by cross-sensitivity and the complexity of multi sensor integration. Here, we present a dual-dip heterogeneous long-period fiber grating (LPFG) sensing platform enabled by…

Optics · Physics 2026-05-12 Cuiying Huang , Riming Xu , Jialing Kang , Weihan Chen , Xingnan Chen , Yanbo Li , Jin Wang

The large transparency window of silicon, covering the 1.1 um 8 um wavelength range, makes it a promising platform for the implementation of photothermal-based absorption spectrometers. These devices indirectly sense absorption in the…

The measurement of very low reflection coefficients of anti-reflective coated interfaces has become a key issue for the realization of precision instruments such as the giant interferometers used for the detection of gravitational waves. We…

Optics · Physics 2023-03-22 Michel Lequime , Imran Khan , Myriam Zerrad , Claude Amra

Refractive index is a fundamental optical property of powder and a key input to the measurement of the size distribution using light scattering and the measurement of the absorption and scattering coefficients using diffuse reflectance…

Optics · Physics 2024-03-05 Cory Juntunen , Adam J. Rish , Carl Anderson , Yongjin Sung

Photonic biosensors that use optical resonances to amplify signals from refractive index changes offer high-sensitivity, real-time readout, and scalable, low-cost fabrication. However, when used with classic affinity assays they struggle…

Applied Physics · Physics 2021-02-10 Michael Dubrovsky , Morgan Blevins , Svetlana V. Boriskina , Diedrik Vermeulen

This paper describes the spherical concave mirror method for measuring the index of refraction of transparent liquids. We derived the refractive index equation using Snell's law and the small-angle approximation. We also verified the…

Classical Physics · Physics 2013-01-22 Amitabh Joshi , Juan D. Serna

Precision optical filters are key components for current and future photonic technologies. Here, we demonstrate a low loss spectral filter consisting of an ultrasteep bandpass feature with a maximum gradient of (90.6$\pm$0.7) dB/GHz,…

Highly dispersive photonic band-gap-edge optofluidic biosensors are studied theoretically. We demonstrate that these structures are strongly sensitive to the refractive index of the liquid, which is used to tune dispersion of the photonic…

Optics · Physics 2007-05-23 Sanshui Xiao , Niels Asger Mortensen

Recent experiments at free-electron laser x-ray sources have been able to resolve the intensity distributions about Bragg peaks in nanocrystals of large biomolecules. Information derived from small shifts in the peak positions augment the…

Data Analysis, Statistics and Probability · Physics 2013-06-05 Veit Elser