Register to reply

Near field of a diffraction grating?

Share this thread:
pjbeierle
#1
May14-14, 06:37 PM
P: 7
I know one can find the "near field" length of an illuminated diffraction grating by calculating the Talbot Length, but I also know this is not the complete story. What happens when you have instead a light source (like a laser beam) that coherently illuminates a certain number of grating bars/slits , say 8 or 9 open slits. How would one calculate the length of the near field then? it seems that the near field length would increase with the number of slits you coherently illuminate.

Can someone provide me with a better equation or method for finding the near field length?

Thanks in advance
Phys.Org News Partner Physics news on Phys.org
New complex oxides could advance memory devices
'Squid skin' metamaterials project yields vivid color display
Scientists control surface tension to manipulate liquid metals (w/ Video)
Claude Bile
#2
May16-14, 11:18 AM
Sci Advisor
P: 1,477
The standard approach for a scalar field is to;

1. Calculate the angular spectrum at the aperture (This is the Fourier transform of the aperture function).
2. Propagate the field forward by adding an angle-dependent phase.
3. Measure the "length" you need.

Claude.


Register to reply

Related Discussions
How do I find the spacing(d) of a grating in a diffraction grating experiment. Introductory Physics Homework 1
Diffraction grating & young double slit -light not perpendicular to grating Introductory Physics Homework 1
Diffraction grating (missing diffraction beam) Introductory Physics Homework 4
Diffraction grating problem, missing orders, diffraction minimum and maximums. Introductory Physics Homework 1
Help w/ diffraction grating Introductory Physics Homework 2