Linked Questions

21
votes
4answers
3k views

Does average lifetime even mean anything?

So today I was trying to derive an expression for the number of radioactive atoms remaining after a time $t$ if I began with $N_0$ atoms in total. At first I tried to assume that they had an average ...
11
votes
5answers
2k views

Plants and quantum mechanics!

I have been working on quantum biology and found something interesting that I would like to write an equation for. Scientists have wondered how plants have such a high efficiency in photosynthesis; ...
11
votes
5answers
3k views

Does an electron move from one excitation state to another, or jump?

I'm wondering, when an electron changes state, does it move from one state to another over some (very small) time period? Or does it change from one state to another in no time? If the former, what ...
4
votes
5answers
1k views

Why is the bandwidth of a 'monochromatic' laser beam not zero?

A basic laser stimulates a gain medium's electrons with an optical pump. One of the excited electrons decays to a lower energy level, emitting a photon with some frequency. This photon bounces in the ...
1
vote
2answers
13k views

Full Width Half Maximum (FWHM) of a transmission spectrum

I have a transmission spectrum of a material which has been fit to a Lorentzian. According to Wikipedia here and here, FWHM is the spectral width which is wavelength interval over which the ...
2
votes
3answers
620 views

Can one build a laser using spontaneous emission?

We use stimulated emission and not spontaneous emission to produce lasers. Why is this? Can't we produce lasers by the spontaneous emission method?
3
votes
1answer
326 views

What determines the form of the intensity curves in Laser-Induced Fluorescence (LIF) measurements?

What determines the form of the intensity spectra of different particle species in Laser-Induced Fluorescence (LIF) measurements? See e.g. I figure that bigger particles have more ways to get ...
2
votes
1answer
315 views

What does it mean for an electromagnetic structure to be resonant?

There are many electromagnetic structures used in microwave engineering and EM devices. For example, patch antennas, metamaterials made from unit cells, etc. When they design structures like patch ...
5
votes
1answer
202 views

Is a GASER a theoretical possibility? [closed]

This question (basically an analogy ) is inspired by several questions and answers that appeared on stackexchange.  We first define GASER, for the purpose of this question. GASER - gravitational (...
0
votes
1answer
111 views

Fourier Transform of E-Field with Decay Constant

Given an atomic transition with associated E-field $E(t) = E_{0}\cos(\omega_{0}t)e^{-t/\tau}$ where $\omega_{0}$ is the natural line frequency and $\tau$ is the decay constant of the simple harmonic ...
0
votes
1answer
94 views

Laser as an optical oscillator

How can Laser can be compared to a positive feedback amplifier? Does the two conditions for oscillator holds good for lasers too.
2
votes
0answers
102 views

Conditions for allowed modes in Quantization of an EM Field

Usualy, when quantizing a free Electromagnetic Field, the first thing we do is solve the classical Maxwell Equations, to get a full set of modes (solutions of the equations) that are then used to ...