Fresnel diffraction Definition and 17 Threads

Why does tilting a diffraction grating tilt the dots as well? This doesn't make sense to me because the lines are still lines when tilted. Even when I consider the phase and consider the gaussian beam that comes in as a superposition of plane waves, what comes out are dots in a straight line...

For the first part, I got correct: M = (lambda*f)/r_n Converting units to meters (m) then plugging them in: (550x10^-9 m) * (0.67 m)/(0.0125 m) = 2.948x10^-5 or 29.48x10^-6 m or 29.48 nm This checked out. For the second part, using the information from the first part: f = r^2/(n*lambda) =...

Hello everybody I am currently looking at diffraction through a rectangular aperture. I am looking at an aperture which is large compared to wavelength, and am looking at diffraction at all angles behind the aperture in a distance which is approx equal to the size of the aperture. I am...

I'd appreciate if someone could check whether my work is correct. The ##x##-##y## symmetry of the aperture separates the Fresnel integral:\begin{align*} a_p \propto \int_{-a/2}^{a/2} \mathrm{exp}\left(\frac{ikx^2}{2R} \right) dx \int_{-a/2}^{a/2} \mathrm{exp}\left(\frac{iky^2}{2R} \right) dy...

I am wondering if it is possible to use principals of diffraction to cause a collimated beam of light (laser) to become divergent. I see that zone plates are most always used for focusing the light from a source, unless they are used in reverse. This is why zone plates are seemingly always...

I'm wondering if I can perform an actual experiment to observe Fresnel diffraction. I would like to do it with a rectangular aperture and of course, visible light. What should its dimensions be? And from which distance from it can I expect to start seeing a decent diffraction pattern? I know I...

how can we consider/ visualise a half period zone inside blackened portion of +ve zone plate ?

Hello! I'm very interested in knowing your opinion on how close my model is to the Fresnel Diffraction by an opaque barrier, as seen here: http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/difopa.html#c1 My model: Sorry for the low quality image.

I read in texts that when a rays of light are diffracted from a straight edge, the phenomenon can be explained using the half period zones. The things that is confusing me is this: "Odd number of half period zones, if exposed, lead to a bright fringe. Even number of half period zones exposed...

I constructed my code of the Angular Spectrum Method. However, as the distance between the object and the plane of interest increases, the diffraction pattern never disappears; there is still some sort of a diffraction pattern, and I am expecting that it disappears as distance increases. Here...

I'm trying to simulate the Fresnel Diffraction in MatLab using the Fast Fourier Transform syntax. But I'm not getting really good diffraction patterns. Here is the code: %% Fourier Transform for G(p, q) g = layer.*exp(((1i*pi)/(lambda*z))*(r_obj)); G = fftshift(fft2(g)); %% Fourier Transform...

Considering this system (from Wikipedia), The Fresnel Diffraction at x, y, and z is ##E \left(x, y, z\right) = \frac{z}{i \lambda} \int \int^{+\infty}_{-\infty} E \left(x', y', 0\right) \frac{e^{ikr}}{r^2} dx' dy'## where ##r = \sqrt{\left(x - x'\right)^2 + \left(y - y'\right)^2 + z^2}##...

I would like to see the difference between Fraunhofer and Fresnel diffraction with a homemade setup. Has anyone achieved this? In this example, it seems that the main components are a He-Ne laser, a short-focal lens, a pinhole and an adjustable aperture. I have some doubts about the possible...

Hi guys, I can't find my notes on Fresnel diffraction and I have my Optics exam on Monday... Does anyone know how to derive F=a2/λL where L=1/z+1/z' I've googled it to death, checked here and tried in Optics 4th edition by Hecht with no luck... I'd really appreciate any help...

Hi Everyone, I am having trouble with my Fourier optics. I am trying to simulate Fresnel diffraction using the following form of the equations: Li(xi, yi) = K * magnitude (FT{ P(xp, yp)E(xp, yp) } p= xi/ld ;q= yi/ld) ^2 K = 1/(ld)^2 E(xp, yp) = e^(i*(PI/ld)*(xp^2+yp^2)) P is the...

What is geometrical shadow qualitatively? please don't refer me to hyper physics

Hey people... This isn't really a homewrok question, I am asking it to try and improve my understanding, but if i still have posted it in the wrong place i sincerely apologise if i upset anyone. I am going over some notes before my exam in 4 days and have encountered a problem... the...