Coherent Sources
Coherent Sources - Related Videos
10:39
Measurement of X-ray Beam Coherence along Multiple Directions Using 2-D Checkerboard Phase Grating
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Cited by 10 •
2016
The measurement protocol and data analysis procedure are given for obtaining transverse coherence of a synchrotron radiation X-ray source along four directions simultaneously using a single 2-D checkerboard phase grating. This simple technique can be applied for complete transverse coherence characterization of X-ray sources and X-ray optics.
11:21
Integrated Photoacoustic Ophthalmoscopy and Spectral-domain Optical Coherence Tomography
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Cited by 24 •
2013
Photoacoustic ophthalmology (PAOM), an optical-absorption-based imaging modality, provides the complementary evaluation of the retina to the currently available ophthalmic imaging technologies. We report the using of PAOM integrated with spectral-domain optical coherence tomography (SD-OCT) for simultaneous multimodal retinal imaging in rats.
04:08
In Vivo Imaging of the Mouse Retina Using Optical Coherence Tomography
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2025
Source: Jagodzinska, J., et. al., Optical Coherence Tomography: Imaging Mouse Retinal Ganglion Cells In Vivo. J. Vis. Exp. (2017) In this video, we demonstrate the use of spectral-domain optical coherence tomography (SD-OCT) to image retinal layers and assess structural changes in a genetically modified mouse model with optic neuropathy.
12:56
Differential Imaging of Biological Structures with Doubly-resonant Coherent Anti-stokes Raman Scattering (CARS)
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Cited by 2 •
2010
A combination of three single wavelength short-pulsed lasers is used to generate coherent anti-Stokes Raman scattering (CARS) and doubly-resonant CARS (DR-CARS). The difference between these signals provides enhanced sensitivity for otherwise difficult to detect coherent Raman signals, enabling imaging of weak Raman scatterers.
15:58
Measurement of Coherence Decay in GaMnAs Using Femtosecond Four-wave Mixing
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Cited by 3 •
2013
The technique of femtosecond four-wave mixing is described, including spectrally-resolved and time-resolved configurations. We illustrate the utility of this technique for the investigation of crucial physical properties in the III-V diluted magnetic semiconductors, afforded by its nonlinearity and high temporal resolution.
FAQs
A stable phase relationship makes the combined electric fields behave predictably at different locations. Their relative phase determines whether the overlap is constructive or destructive, producing a stable interference pattern rather than one that changes unpredictably. In physics, this stability allows researchers to connect observed intensity variations with wave behavior and use them for precise measurements.
Coherence length sets the distance over which the waves can maintain the phase relationship needed for reliable interference. If the path difference exceeds this length, the expected constructive and destructive pattern is no longer maintained. Consequently, experimental arrangements must keep relevant path differences within the coherence length when stable interference measurements are required.
In the overview's laser example, stimulated emission and optical resonance are associated with producing light that maintains the frequency and phase conditions required for coherence. These processes help provide controlled optical waves rather than relying on an uncontrolled phase relationship. That control makes laser light useful in measurements and technologies based on interference and phase information.
Interferometry uses the predictable interference of coherent waves to obtain measurement information from changes in the resulting pattern. Because constructive and destructive contributions depend on the waves' phase relationship and path difference, the pattern can reveal precise variations in an optical arrangement. This makes coherent sources important whenever physics experiments require controlled comparison of wave behavior.
Holography and diffraction measurements depend on controlled light and observable wave-interference behavior. Coherent sources provide the stable phase conditions needed for interference patterns to remain interpretable, while the resulting patterns support examination of optical wave behavior. Their use therefore connects the phase properties of light with experimental methods for recording or measuring structured wave effects.
Optical communications can benefit from sources that maintain controlled phase and frequency properties, because these properties preserve usable phase information in light. Coherent sources therefore support technologies in which optical signals must be controlled rather than treated as unpredictable waves. Their role reflects the broader importance of manipulating light precisely for transmitting information.
Precision sensing relies on detecting small, meaningful changes in a controlled physical signal. Coherent sources make such detection possible by producing stable interference conditions, so changes can be related to phase behavior or path difference rather than uncontrolled source variation. This connects coherent optical waves with sensitive measurements and with broader studies of wave behavior in physics.