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However, such processes generally do not require the assumption of photons per se; they may often be modeled by treating atoms as nonlinear oscillators. The nonlinear process of spontaneous parametric down conversion is often used to produce single-photon states.
Biophotons may be detected with photomultipliers or by means of an ultra low noise CCD camera to produce an image, using an exposure time of typically 15 minutes for plant materials. [ 9 ] [ 3 ] Photomultiplier tubes have been used to measure biophoton emissions from fish eggs, [ 10 ] and some applications have measured biophotons from animals ...
Photobiology is the scientific study of the beneficial and harmful interactions of light (technically, non-ionizing radiation) in living organisms. [1] The field includes the study of photophysics, photochemistry, photosynthesis, photomorphogenesis, visual processing, circadian rhythms, photomovement, bioluminescence, and ultraviolet radiation effects.
The great biological importance of photoreceptors is that they convert light (visible electromagnetic radiation) into signals that can stimulate biological processes. To be more specific, photoreceptor proteins in the cell absorb photons , triggering a change in the cell's membrane potential .
This return to stability corresponds with the release of excess energy in the form of fluorescent light. This emission of light is only observable whilst the excitation light is still providing photons to the fluorescent molecule and is typically excited by blue or green light and emits purple, yellow, orange, green, cyan, or red.
A white light source—emitting light of multiple wavelengths—is focused on a sample (the pairs of complementary colors are indicated by the yellow dotted lines). Upon striking the sample, photons that match the energy gap of the molecules present (green light in this example) are absorbed, exciting the molecules. Other photons are scattered ...
The former is typically a fast process, yet some amount of the original energy is dissipated so that re-emitted light photons will have lower energy than did the absorbed excitation photons. The re-emitted photon in this case is said to be red shifted, referring to the reduced energy it carries following this loss (as the Jablonski diagram shows).
Photodissociation, photolysis, photodecomposition, or photofragmentation is a chemical reaction in which molecules of a chemical compound are broken down by absorption of light or photons. It is defined as the interaction of one or more photons with one target molecule that dissociates into two fragments. [1]