Ad
related to: calculating number of photons given water
Search results
Results From The WOW.Com Content Network
The regimes are defined by the relationship between the variance and average number of photon counts for the corresponding distribution. Both Poissonian and super-Poissonian light can be described by a semi-classical theory in which the light source is modeled as an electromagnetic wave and the atom is modeled according to quantum mechanics.
The fluorescence quantum yield is defined as the ratio of the number of photons emitted to the number of photons ... Water 280 0.13 ± 0.01 ... that a given quantum ...
Photon counting eliminates gain noise, where the proportionality constant between analog signal out and number of photons varies randomly. Thus, the excess noise factor of a photon-counting detector is unity, and the achievable signal-to-noise ratio for a fixed number of photons is generally higher than the same detector without photon counting.
Photons can be scattered by matter. For example, photons scatter so many times in the solar radiative zone after leaving the core of the Sun that radiant energy takes about a million years to reach the convection zone. [116] However, photons emitted from the sun's photosphere take only 8.3 minutes to reach Earth. [117]
is the number operator. When acting on a quantum mechanical photon number state, it returns the number of photons in mode (k, μ). This also holds when the number of photons in this mode is zero, then the number operator returns zero. To show the action of the number operator on a one-photon ket, we consider
Quantitatively, the number of photons absorbed, between the points and + along the path of a beam is the product of the number of photons penetrating to depth times the number of absorbing molecules per unit volume times the absorption cross section :
where ℓ is the mean free path, n is the number of target particles per unit volume, and σ is the effective cross-sectional area for collision. The area of the slab is L 2, and its volume is L 2 dx. The typical number of stopping atoms in the slab is the concentration n times the volume, i.e., n L 2 dx. The probability that a beam particle ...
count of photons n with energy Q p = h c/λ. [nb 2] photon flux: Φ q: count per second: s −1: T −1: photons per unit time, dn/dt with n = photon number. also called photon power: photon intensity: I: count per steradian per second sr −1 ⋅s −1: T −1: dn/dω: photon radiance: L q: count per square metre per steradian per second m − ...