# What is Optical absorption: Definition and 11 Discussions

In physics, absorption of electromagnetic radiation is how matter (typically electrons bound in atoms) takes up a photon's energy — and so transforms electromagnetic energy into internal energy of the absorber (for example, thermal energy). A notable effect is attenuation, or the gradual reduction of the intensity of light waves as they propagate through a medium. Although the absorption of waves does not usually depend on their intensity (linear absorption), in certain conditions (optics) the medium's transparency changes by a factor that varies as a function of wave intensity, and saturable absorption (or nonlinear absorption) occurs.

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1. ### Absorption coefficient and Linear Optical Susceptibility

##\alpha## is considered to be the absorption coefficient for a beam of light of maximum intensity ##I_0##. It's related to the complex part of the refractive index as we have shown above. Now, I have a doubt. Should I solve for ##k## from the quadratic equation in terms of the linear optical...
2. ### I Spin and wavefunction of excitons

My Bachelor thesis is all around Excitons (specifially transitions between excitons of different energies). During my work I often had trouble with the spin and the wavefunction of them. Is there maybe some good (free) literature about the theory of excitons ? I found some books in the internet...
3. ### A How to calculate the temperature change of a laser-irradiated material

I am looking to approximately calculate the temperature change of a sample that was exposed to a laser pulse. Experimentally, we know the optical absorption, reflection, and transmission, as well as the source parameters for our laser system. I realize that I will have to make approximations...

5. ### Second reflection angle of incidences in 3D

Given Theta1(angle of incidence) and alpha1(azimuth angle). how do we obtain the second reflection angle theta3 and alpha3? Assuming the surface to be a mirror reflection(theta1 = theta2). Need an equation when varied the incident angles we would obtain the second reflection angles or a method...
6. ### A Deconvolution of the optical absorption spectra

Hi people, i am doing the deconvolution of the optical absorption spectra of some quartz samples . The optical absorption spectra were obtained following a step annealing procedure.For the deconvolution i am using the Origin 9, so my question is.. Why in some articles i find the deconvolution...
7. ### Possibility of optical absorption by defect level in bandgap

Hi, I have a tricky question regards the absorption of photons by semiconductor. Say I got a piece of semiconductor with Eg=4eV. Inside the bandgap, there are two defect levels, and each of them have a trapped electron. One of the defect has the energy level that is 1eV below conduction...
8. ### Perturbing Hamiltonian optical absorption in semiconductors

Hi I am looking at the problem of optical absorption in direct gap semiconductors. It seems like the perturbing Hamiltonian is an oscillating perturbation , ie. an electromagnetic wave. Why can't the problem be treated as the absorption of a single particle , ie. a photon ?
9. ### How to Determine Band Gap of Amorphous Materials Using Optical Absorption Edge

Hello, I am trying to determine the band gap of an amorphous material (a glass sample) and I read that you can do this from the determination of the optical absorption edge. From this kind of measurements you fitt an equation of the type (αhν) = B (hv-Eo) 2. my question are: 1 - is it...
10. ### Optical absorption liquid vs solid

I'm looking for information about absorption of light per unit (atom, molecule, stoichiometric) in a liquid vs solid. For instance, imagine a unit cube filled with a saturated solution of, say, potassium permanganate, and shine a laser beam through it from bottom to top and measure the...
11. ### Optical absorption in Semiconductors

[SOLVED] Optical absorption in Semiconductors Homework Statement I'm doing a lab report on the optical absorption of semiconductors. More specifically it was to determine the bandgap values of the semiconductor samples. This is the experimental setup...