I'm looking for penetration depth of GaAs. I was using 532nm laser. Is it simply 1/a? (a:absoprtion coefficient) Help me, plz. T.T
As I know, depth is related to focal spot size and wavelength of incident wave in vacume.
depth=k.w^2(w=spot size)
k=(2*3.14)/(landa/n) (landa:wavelength)(n:refractive index)
You can find some useful theoretical insight into your question on this link. They have given the plots of the penetration depth vs. the wavelength for different materials.
https://www.princeton.edu/~spikelab/papers/book02.pdf
I think You have first to calculate tis mathematically (via theoritical formula) and then use this parameter in simmulation through a code like ELK.
Martin is right. Depth = 0.14 um
See http://refractiveindex.info/?shelf=main&book=GaAs&page=Jellison
Guys: there is some mess in the definition:
first of all for the question - GaAs is very absorptive material in 532nm, so yes. Penetration depth is simply 1/absorption coefficient.
There is another situation, where the term "penetration depth" is used - it is a case of total internal reflection. When EM wave (or if you wish a ray) is traveling from a medium with high refractive index toward a medium with lower refractive index, if the angle of incidence on the interface between two media is above some critical angle (easy to calculate using Snell's law, but say for air-glass interface it is ~43 degrees) it is being reflected back into the optically dense medium, BUT, there is still EM field in the second medium, that is NOT propagating, but exponentially decays from the interface. The decay distance (penetration depth) depends on refractive indexes of both media, angle of incidence and wavelength. The formula provided by Zahra seams to be a special case for penetration depth used in TIR microscopy, or something like that, in general, it is not hard to calculate for simple interfaces.
Generally speaking - all the above is correct.
Pen.Depth is basically 1/a, or in case of TIR it is an evanescence field.
BUT if high power is used you must consider some non-linear effects.
Also medium power may pose some deviation form the 1/a 'rule'. You may take a look at- https://www.researchgate.net/publication/236859765_Basic_model_of_absorption_depth_and_injection_levels_in_silicon_under_intermediate_illumination_levels?ev=prf_pub
R
Article Basic model of absorption depth and injection levels in sili...
how to find out the optical penetration depth for the SrTiO3 from refractive index data or absorption coefficient??
dear sir,
I have derived a formula that answers your question. Here is its link
Article On the refractive index and photon mass
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