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- """Simulation of the double slit experiment.
- (Any number of slits of any geometry can be added)
- Slit sources are placed on the plane shown as a thin grid"""
- # Can simulate the 'Arago spot', the bright point at the center of
- # a circular object shadow (https://en.wikipedia.org/wiki/Arago_spot).
- from vedo import *
- #########################################
- lambda1 = 680e-9 # red wavelength 680nm
- width = 10e-6 # slit width in m
- D = 0.1 # screen distance in m
- #########################################
- # create the slits as a set of individual coherent point-like sources
- n = 10 # nr of elementary sources in slit (to control precision).
- slit1 = list(zip([0]*n, np.arange(0,n)*width/n, [0]*n)) # source points inside slit1
- slit2 = list(slit1 + np.array([1e-5, 0, 0])) # a shifted copy of slit 1
- slits = slit1 + slit2
- # slits += list(slit1 + array([-2e-5, 1e-5, 0])) # add another copy of slit1
- # slits = [(cos(x)*4e-5, sin(x)*4e-5, 0) for x in arange(0,2*np.pi, .1)] # Arago spot
- # slits = Grid(s=[1e-4,1e-4], res=[9,9]).points # a square lattice
- screen = Grid(pos=[0, 0, -D], s=[0.1,0.1], lw=0, res=[200,50]).wireframe(False)
- # Compute the image on the far screen
- k = 0.0 + 1j * 2 * np.pi / lambda1 # complex wave number
- norm = len(slits) * 5e5
- amplitudes = []
- verts = screen.points
- for i, x in enumerate(verts):
- psi = 0
- for s in slits:
- r = mag(x - s)
- psi += np.exp(k * r) / r
- psi2 = np.real(psi * np.conj(psi)) # psi squared
- amplitudes.append(psi2)
- verts[i] = x + [0, 0, psi2 / norm]
- screen.cmap("hot", amplitudes)
- plt = Plotter(title="The Double Slit Experiment", axes=9, bg="black")
- plt += [screen, __doc__]
- plt += Points(np.array(slits) * 200).color("w") # slits scale magnified by factor 200
- plt += Grid(s=[0.1,0.1], res=[6,6],).color("w",0.1)
- plt += Line([0, 0, 0], [0, 0, -D],).color("w",0.1)
- plt += Text3D("source plane", pos=[-0.04, -0.05, 0], s=0.002).c("gray")
- plt += Text3D("detector plane D = "+str(D)+" m", pos=[-.04,-.05,-D+.001], s=.002).c("gray")
- plt.show(zoom=1.15).close()
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