Optical Waveguide
Optical Waveguide - Related Videos
07:28
Terahertz Microfluidic Sensing Using a Parallel-plate Waveguide Sensor
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Cited by 3 •
2012
The procedure for implementing a refractive index sensor for terahertz frequencies based on a grooved parallel-plate waveguide geometry is described here. The method yields a measurement of the refractive index of a small volume of liquid through monitoring of the shift in the resonant frequency of the waveguide...
11:08
Fabrication And Characterization Of Photonic Crystal Slow Light Waveguides And Cavities
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Cited by 14 •
2012
Use of photonic crystal slow light waveguides and cavities has been widely adopted by the photonics community in many differing applications. Therefore fabrication and characterization of these devices are of great interest. This paper outlines our fabrication technique and two optical characterization methods, namely: interferometric (waveguides) and resonant scattering (cavities).
08:31
Three-dimensional Optical-resolution Photoacoustic Microscopy
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Cited by 27 •
2011
Optical-resolution photoacoustic microscopy (OR-PAM) is an emerging technology capable of imaging optical absorption contrasts in vivo with cellular resolution and sensitivity. Here, we provide a visualized instruction on the experimental protocols of OR-PAM, including system configuration, system alignment, typical in vivo experimental procedures, and functional imaging schemes.
08:01
Fabrication of Zero Mode Waveguides for High Concentration Single Molecule Microscopy
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Cited by 3 •
2020
Described here is a nanosphere lithography method for parallel fabrication of zero mode waveguides, which are arrays of nanoapertures in a metal-clad glass microscopy coverslip for single molecule imaging at nano- to micromolar concentrations of fluorophores. The method takes advantage of colloidal crystal self-assembly to create a waveguide template.
09:39
Optical Biosensing
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2023
Optical biosensors utilize light to detect the binding of a target molecule. These sensors can utilize a label molecule, which produces a measurable signal such as fluorescence, or these sensors can be label-free and use the changes in optical properties, such as refractive index, to sense for the binding of the target molecule. This video introduces both label and label-free optical biosensors, demonstrates their use in the laboratory, and shows some applications of the technology.
FAQs
An Optical Waveguide relies on a core with a higher refractive index than its surrounding cladding. This contrast supports total internal reflection, which keeps light traveling along the intended path rather than escaping. In biochemical sensing, stable confinement is important because the guided signal must remain sufficiently controlled for nearby molecular effects to be measured.
The guided light produces a small evanescent field that extends beyond the waveguide surface. Molecules located in this nearby region can influence the optical signal through absorption, fluorescence, or changes in refractive index. This interaction connects a confined optical mode with the surrounding biochemical environment, allowing molecular events near the surface to affect measurement.
Three signal types described for biochemical use are absorption, fluorescence, and refractive-index effects. A molecular interaction may therefore be followed by monitoring how transmitted light changes through one of these optical responses. These alternatives provide different ways to observe biochemical events, while the waveguide supplies the common platform for transporting and monitoring the optical signal.
Detection depends on whether the analyte lies within the region reached by the evanescent field and whether its interaction produces a measurable optical change. Relevant changes include absorption, fluorescence, or refractive-index variation. Consequently, waveguide design and analyte proximity matter together: confinement transports the signal, while the extended field connects it to the biochemical sample.
A basic measurement links a guided optical signal to a biochemical sample positioned near the waveguide surface. The transmitted light is observed for changes associated with absorption, fluorescence, or refractive-index effects. When binding alters one of these responses, the resulting optical variation provides evidence that the molecular environment near the guide has changed.
The overview identifies proteins, nucleic acids, and other analytes as targets for waveguide-based biochemical measurements. The approach is especially relevant when researchers want label-free biosensing or monitoring of molecular binding. It provides a way to connect changes in a photonic signal with biochemical events across multiple analyte types rather than a single target class.