number density

(redirected from Photon density)
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number density

[′nəm·bər ‚den·səd·ē]
(physics)
The number of particles per unit volume.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Ultrashort pulse lasers present a class of laser beam sources for industrial applications that offer outstanding features with respect to intensity, photon density and pulse duration.
where r denotes the position, [PHI] is the photon density, Q is the source term, and [u.sub.a] D are the absorption and diffusion coefficients, respectively.
[phi](r, t) photon density at ([m.sup.-3]) point r, at time t 10.
In this case, the key factor that determines nonlinearity is photon density. At the same time thermal effect also plays an important role in cell damage due to high single-photon absorption by water and heat generation in nonlinear processes.
This is paramount because the probability for a photon absorption event to occur largely depends on the photon density or fluence rate and the photon absorption cross section of the molecule where the former may be influenced by the pulse repetition rate and the peak power.
Here [L.sub.p] = [(Gh/[c.sup.3]).sup.1/2] is the Planck length, [n.sub.c] = [u.sub.c]/[bar.E] a characteristic photon density, and [bar.[lambda]] = c/[bar.v].
Based on a multi-layered semiconducting structure, which serves as a medium to build up photon density that can also be tailored to emit at different wavelengths, the QC laser has proven to be a compact, useful light source for many applications.