Prism Coupling
Prism Coupling - Related Videos
11:45
Quantifying Agonist Activity at G Protein-coupled Receptors
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Cited by 10 •
2011
A method for estimating the affinity constant of an agonist for the active state (Kb) of a G protein-coupled receptor is described. The analysis provides absolute or relative measures of Kb depending on whether constitutive receptor activation is measurable. Our method applies to various responses downstream from receptor activation.
10:35
Multi-layer Cortical Ca2+ Imaging in Freely Moving Mice with Prism Probes and Miniaturized Fluorescence Microscopy
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Cited by 26 •
2017
Here, we present a procedure for performing large-scale Ca2+ imaging with cellular-resolution across multiple cortical layers in freely moving mice. Hundreds of active cells can be observed simultaneously using a miniature, head-mounted microscope coupled with an implanted prism probe.
01:20
Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)
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2024
Two NMR-active nuclei bonded to a central atom can be involved in geminal or two-bond coupling. Geminal coupling is commonly seen between diastereotopic protons in chiral molecules and unsymmetrical alkenes, among others. The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
01:22
Spin–Spin Coupling: Three-Bond Coupling (Vicinal Coupling)
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2024
Vicinal or three-bond coupling is commonly observed between protons attached to adjacent carbons. Here, nuclear spin information is primarily transferred via electron spin interactions between adjacent C‑H bond orbitals. This generally favors the antiparallel arrangement of spins, so 3J values are usually positive. The extent of coupling depends on the C‑C bond length, the two H‑C‑C angles, any electron-withdrawing substituents, and the dihedral angle between the involved orbitals. The...
06:19
Palladium-Catalyzed Cross Coupling
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2023
Source: Vy M. Dong and Faben Cruz, Department of Chemistry, University of California, Irvine, CA This experiment will demonstrate the concept of a palladium-catalyzed cross coupling. The set-up of a typical Pd-catalyzed cross coupling reaction will be illustrated. Pd-catalyzed cross coupling reactions have had a profound effect on how synthetic chemists create molecules. These reactions have enabled chemists to construct bonds in new and more efficient ways. Such reactions have found widespread...
FAQs
Phase matching aligns the optical conditions at the prism interface with the propagation conditions of a guided mode. At the appropriate prism angle, the evanescent field can transfer energy efficiently into that mode rather than remaining only in the reflected beam. Identifying this angular condition reveals which guided modes are supported and enables optical characterization.
Total internal reflection creates the evanescent field that extends from the prism toward the adjacent waveguide without propagating freely away from the interface. That near-field interaction supplies the coupling pathway. If this field cannot interact with the nearby waveguide, the phase-matching response required to observe transfer into a guided mode will not appear.
During prism coupling, a reflected-intensity change signals that some incident optical energy is being transferred into a waveguide mode under phase-matched conditions. Recording this response as the prism angle changes helps locate the angles associated with guided modes. The measured coupling behavior can then support determination of film thickness, refractive index, propagation losses, and modal characteristics.
Film thickness and refractive index are key optical quantities that prism coupling can determine from guided-mode behavior. Their values affect the optical response observed when the prism angle reaches phase-matching conditions. Analyzing that response provides a way to characterize planar films and waveguiding structures, while also supplying information about their supported modal characteristics.
An optical arrangement places a high-refractive-index prism near a planar waveguide, directs light into the prism under total internal reflection, and monitors reflected intensity while the prism angle is adjusted. The angle at which phase matching occurs marks coupling to a guided mode. Analysis of these responses can yield film thickness, refractive index, propagation losses, and modal characteristics.
In engineering, these measurements support the development of integrated optical devices, sensors, and photonic materials. Film thickness, refractive index, propagation loss, and modal characteristics describe important properties of planar optical structures. Prism coupling therefore connects an optical measurement with the evaluation and refinement of waveguiding components and sensing platforms.