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This paper proposes an alternative method for grating period measurement based on heterodyne grating interferometry. The optical configurations for measuring the period of reflection/transmission gratings were demonstrated, and four commercially available gratings were used to evaluate the effectiveness of the proposed method. Based on the phase-lock technique, the grating period could be obtained immediately through the phase wrapped/unwrapped process. Under precise measurement conditions, the grating period measurement error of the proposed method was better than 1 nm, and the grating period difference between product specifications was less than 1%. In addition, the measurement results of the proposed method also exhibited high similarity with optical microscopy measurements.
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http://dx.doi.org/10.1364/AO.521993 | DOI Listing |
ACS Appl Nano Mater
August 2025
Department of Physics, School of Science and Technology, Nottingham Trent University, Nottingham NG11 8NS, United Kingdom.
Accurate and noninvasive detection of cancer cells is critical for advancing early stage cancer diagnostics and monitoring tumor progression. While manual enumeration methods, such as hemocytometry, remain in use, they suffer from limited sensitivity and scalability. In this article, we report the first feasibility study demonstrating a graphene oxide (GO)-functionalized long-period fiber grating (LPG) sensor for the label-free detection of MCF-7 human breast cancer cell density via secreted cellular byproducts.
View Article and Find Full Text PDFNanophotonics
August 2025
Hangzhou Institute of Technology, Xidian University, 311200, Hangzhou, China.
Optically variable features are widely used in product design and anti-counterfeiting. However, current industrial methods rely heavily on chemical inks, which pose environmental concerns and suffer from poor wear and corrosion resistance. We experimentally demonstrate the generation of non-iridescent yet angle-dependent structural colors on titanium surfaces using a nanosecond laser-induced oxidation.
View Article and Find Full Text PDFNanophotonics
August 2025
Department of Electronic Engineering, Hanyang University, Seoul, 04763, Republic of Korea.
Under-display camera (UDC) systems enable full-screen displays in smartphones by embedding the camera beneath the display panel, eliminating the need for notches or punch holes. However, the periodic pixel structures of display panels introduce significant optical diffraction effects, leading to imaging artifacts and degraded visual quality. Conventional approaches to mitigate these distortions, such as deep learning-based image reconstruction, are often computationally expensive and unsuitable for real-time applications in consumer electronics.
View Article and Find Full Text PDFNanoscale Adv
July 2025
Department of Atomic and Molecular Physics, Faculty of Physics, Alzahra University Tehran 1993893973 Iran.
Smart windows automatically adjust their properties to control infrared (IR) radiation which helps with saving energy by reducing the need for heating and cooling. In the current study, we use vanadium dioxide (VO), a phase change material that in temperatures above 68 °C behaves as a metal, to design smart windows. In its metallic phase, VO transmits less IR than would be expected from a smart window.
View Article and Find Full Text PDFDalton Trans
September 2025
Jiangsu Key Laboratory for Optoelectronic Detection of Atmosphere and Ocean, Nanjing University of Information Science and Technology, Nanjing, Jiangsu 210044, China.
We propose a dynamically tunable and angle-robust mid-infrared (mid-IR) absorber based on a hybrid metastructure composed of a top-layer Ge grating, an ultrathin SrTiO polar dielectric layer, a thermochromic VO film, and a metallic substrate. The optical response of the system is modeled using rigorous coupled-wave analysis (RCWA), revealing broadband and high-efficiency absorption across a wide range of incident angles (0°-80°) under transverse-magnetic (TM) polarization. The absorption behavior is governed by the interplay of multiple resonant mechanisms, including guided-mode resonance (GMR) in the Ge grating, phonon-polariton (PhP) excitation in the SrTiO layer, and cavity-like modes facilitated by the insulating VO.
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