Wavelength scanning interferometry is an interferometric technique for measuring surface topography without the well-known 2π phase ambiguity limitation. The measurement accuracy and resolution of this technique depends, among other factors, on th...
The two peaks characteristic of yellow and blue light in the spectrum of dual-wavelength white light emitting diodes (LEDs) introduce distinctive features to the interference signal of white light scanning interferometry (WLSI). The distinctive featu...
A fast surface plasmon resonance (SPR) imaging biosensor system based on wavelength interrogation using an acousto-optic tunable filter (AOTF) and a white light laser is presented. The system combines the merits of a wide-dynamic detection range and...
Recently, there has been growing interest in using lightwave-driven scanning probe microscopy (LD-SPM) to break through the Abbe diffraction limit of focusing, yielding insight into various energy couplings and conversion processes and revealing the...
We demonstrated a 1.1-µm band extended wideband wavelength-swept laser (WSL) that combined two semiconductor optical amplifiers (SOAs) based on a polygonal scanning wavelength filter. The center wavelengths of the two SOAs were 1020 nm and 1140 nm, r...
We introduce wavelength-scanning coherent optical time domain reflectometry (WS-COTDR) for dynamic vibration sensing along optical fibers. The method is based on spectral shift computation from Rayleigh backscatter spectra. Artificial neural networks...
Recently, terrestrial laser scanning (TLS) has shown potential in measuring vegetation biochemical traits in three dimensions (3D) by using reflectance derived from backscattered intensity data. The 3D estimates can provide information about the vert...
Little is known about the temperature dependence of electron transfer occurring at real metal surfaces. For iron surfaces scratched in seven environments, we report Arrhenius activation energies obtained from the data of photoelectron emission (PE) a...
In spectrometer measurement, it is very important to accurately calibrate the wavelength of all target characteristic spectra. Although wavelength calibration methods have long been investigated, no techniques have been designed for the scanning, dou...
In order to obtain optical nonlinear materials with high transparency and low propagation loss in the visible and infrared range, noble metal materials in the off-resonant band have become a hot spot in the optical field in recent years. Therefore, t...
To address the limitations of unsound physical models and the lack of compensation mechanisms in existing multi-degree-of-freedom programmable lighting methods, we proposed a novel multi-degree-of-freedom programmable lighting approach. The maximum d...
(1) Background: The fundus examination is one of the best and popular methods in the assessment of vascular status in the human body. Direct viewing of retinal vessels by ophthalmoscopy has been utilized in judging hypertensive change or arterioscler...
Surface processes such as coatings, corrosion, photocatalysis, and tribology are greatly diversified by acid–base interactions at the surface overlayer. This study focuses on the action of a metallic copper surface as an electron donor/acceptor...
We report here the development of a compact, open-path CO2 and H2O sensor based on the newly introduced scanned-wavelength modulation spectroscopy with the first harmonic phase angle (scanned-WMS-θ1f) method for high-sensitivity, high temporal...
Cementitious materials are used to construct an engineered barrier in repositories for radioactive waste. The cement matrix may contain a variety of organic compounds, some of which are polymeric admixtures used as plasticizers. Superplasticizers (SP...
We report a wavelength swept laser-based full-field optical coherence tomography for measuring the surfaces and thicknesses of refractive and reflective samples. The system consists of a galvo filter–based wavelength swept laser and a simple Michelso...
Pavement skid resistance is significant for driving safety. British Pendulum Number (BPN) is commonly used as a low-speed skid resistance indicator, whereas sometimes it is impractical for data collection on roads in service. Since skid resistance is...
Lidar observations are very useful to analyse dispersed volcanic clouds in the troposphere mainly because of their high range resolution, providing morphological as well as microphysical (size and mass) properties. In this work, we analyse the volcan...
The equidistantly spaced multi-passbands of a Fabry-Perot ITU filter are used as an efficient multi-wavelength reference for fiber Bragg grating sensor demodulation. To compensate for the nonlinear wavelength tuning effect in the FBG sensor demodulat...
Broadband wavelength-swept lasers (WSLs) are widely used as light sources in biophotonics and optical fiber sensors. Herein, we present a polygonal mirror scanning wavelength filter (PMSWF)-based broadband WSL using two semiconductor optical amplifie...
The output of a wavelength-swept laser (WSL) based on a fiber Fabry–Pérot tunable filter (FFP-TF) tends to shift the peak wavelength due to external temperature or heat generated by the FFP-TF itself. Therefore, when measuring the output...
Hyper-spectral imaging (HSI) systems can be divided into two main types as follows: a group of systems that includes a dedicated dispersion/filtering component whose role is to physically separate the different wavelengths and a group of systems that...
This paper presents a miniaturized, broadband near-infrared (NIR) spectrometer with a flame-retardant 4 (FR4)-based scanning micrograte. A 90° off-axis parabolic mirror and a crossed Czerny–Turner structure were used for creating an astigma...
The spatial resolution and light detected in fluorescence imaging for small animals are limited by light scattering, absorption and autofluorescence. To address this, novel near-infrared fluorescent contrast agents and imaging configurations have bee...
Distributed feedback lasers, which feature rapid wavelength tunability, are not presently available in the yellow and orange spectral regions, impeding spectroscopic studies of short-lived species that absorb light in this range. To meet this need, a...
This work presents an asymmetric p-i-p silicon diode structure (a-p-i-p) characterized using the Transient Current Technique (TCT) with a scanning pulsed laser system. The device, fabricated on n-type silicon (3–5 Ω·cm) with two id...
Quartz-enhanced photoacoustic sensing is a promising method for low-concentration trace-gas monitoring due to the resonant signal enhancement provided by a high-Q quartz tuning fork. However, quartz-enhanced photoacoustic spectroscopy (QEPAS) is asso...
Fiber Bragg grating sensors are placed in a fiber-optic Sagnac loop to combine the grating temperature sensors and the fiber-optic mandrel acoustic emission sensors in single optical circuit. A wavelength-scanning fiber-optic laser is used as a commo...
This paper aims to study the nonlinear absorption characteristics of palladium nanoparticles (PdNPs) at off-resonant wavelengths. For this purpose, multi-wavelength (500–650 nm) nanosecond Z-scan technique was used. The experimental results indicate...
Surface Plasmon Resonance imaging (SPRi) is a powerful label-free technique for high-throughput biochemical analysis. Wavelength modulation is particularly suitable for SPRi due to its wide dynamic range and robustness to fabrication tolerances. Howe...
Laser-induced periodic surface structures (LIPSS) is the sub-wavelength periodic nanostructure, which is generally generated by the femtosecond laser. There are two kinds of LIPSS, low spatial frequency LIPSS (LSFL) and high spatial LIPSS (HSFL), and...
In the wavelength modulation spectroscopy (WMS) gas detection system, the laser diode is usually stabilized at a constant temperature and driven by current injection. So, a high-precision temperature controller is indispensable in every WMS system. T...
An external cavity wavelength-fiber ring laser (ECWTFL) based on a semiconductor optical amplifier and a combined wavelength scanning filter in the Littrow configuration is proposed and experimentally demonstrated. With the benefit of the combination...
We report a high-speed (~2 kHz) dynamic multiplexed fiber Bragg grating (FBG) sensor interrogation using a wavelength-swept laser (WSL) with a polygon-scanner-based wavelength filter. The scanning frequency of the WSL is 18 kHz, and the 10 dB scann...
The differences in spatially optical properties between blue and green quantum wells (QWs) in a monolithic dual-wavelength semipolar (20-21) structure were investigated by scanning near-field optical microscopy (SNOM). The shortest wavelength for gre...
Comprehensive and accurate vegetation monitoring is required in forestry and agricultural applications. The optical remote sensing method could be a solution. However, the traditional light detection and ranging (LiDAR) scans a surface to create poin...
Although lasers are widely used in various industries, including aviation, healthcare, and communication engineering, there has been little research concentrated on the field of horticulture. In this paper, five semiconductor pumped fiber-coupled las...
We characterize the nonlinear optical properties of indium–tin oxide (ITO) quantum dots (QDs) in the IR range using the Z-scan method. We present results of three-photon absorption (3PA), third harmonic generation (3HG), and Kerr-effect-induced...
Compared with coupled-mode theory (CMT), which is widely used for studies involving optical fiber Bragg gratings (FBGs), the proposed investigation scheme is visualized, diagrammatic, and simple. This method combines the finite element method (FEM) a...
Hyperspectral imaging technologies in the food and agricultural area have been evolving rapidly over the past 15 years owing to tremendous interest from both academic and industrial fields. Line-scan hyperspectral imaging is a major method that has b...
Radiometric calibration of the Dual-Wavelength Echidna® Lidar (DWEL), a full-waveform terrestrial laser scanner with two simultaneously-pulsing infrared lasers at 1064 nm and 1548 nm, provides accurate dual-wavelength apparent reflectance (ρapp), a p...
The cubic nonlinearity of a graphene-oxide monolayer was characterized through open and closed z−scan experiments, using a nano-second laser operating at a 10 Hz repetition rate and featuring a Gaussian spatial beam profile. The open z−sc...
In this paper, we proposed near-infrared spectroscopy based on a Si photodetector equipped with a gold grating and extended the measurable wavelength range to cover 1200–1600 nm by improving a spectrum derivation procedure. In the spectrum deri...
The roughness spectrum (i.e., the power spectral density) is a derivative of digital terrain models (DTMs) that is used as a surface roughness descriptor in many geomorphological and physical models. Although light detection and ranging (LiDAR) has b...
A thulium-doped fiber laser (TDFL) with a dual-active cavity and a directly linked three-coupler triple-ring filter is designed and demonstrated. Its operational principle is analyzed, and a corresponding experimental setup is built. Eleven single-wa...
Based on the scanning grating mirror we developed, this paper presents a method of the precise control of a scanning grating mirror and of high-speed spectrum data detection. In addition, the system circuit of the scanning grating mirror control and...
Recent years have witnessed growing research interest in dual-wavelength mode-locked fiber lasers for their pivotal role in diverse applications and the exploration of nonlinear dynamics. Despite notable progress in their development, achieving relia...
We present a new laser protective lens based on a multilayered notch filter design with low residual stress and low surface roughness. An18-layer notch filter was prepared by electron beam evaporation with an ion-assisted deposition technique, which...
This paper describes a terahertz (T-ray) cameraless imaging and profile mapping technique for accomplishing the imaging and/or mapping of a whole wafer with fabricated dies for devising a criterion to sort out good dies. A stratagem for decoupling th...
The impact of wavelength and pulse duration in laser cleaning of hard blackish contaminants crust from archaeologically significant Pleistocene bone is investigated in this research. The objective is to determine the practical cleaning procedures and...
of 19