71 lines
4.1 KiB
Python
71 lines
4.1 KiB
Python
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import BeamPropagation as bp # This is the script that handles the propagation
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import sympy as sym # For Symbolic examples
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import numpy as np # Handling of lists and for plotting
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import matplotlib.pyplot as plt # Plotting
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"""A Gaussian beam can be defined by it's (radial) waist wo, it's Rayleigh range zR, and the location of its waist zO"""
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w0 = 5.2E-3 # 1mm beam waist
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lam = 532E-9 # wavelength of 355 nm (UV)
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zR = bp.Zr(w0, lam) # Rayleigh range in m
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z0 = 0 # location of waist in m
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"""Define first 4-f optical system using matrices"""
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d1, d2, d3, f1, f2 = sym.symbols('d1 d2 d3 f1 f2')
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M = bp.mult(bp.prop(d3),bp.lens(f2),bp.prop(d2), bp.lens(f1), bp.prop(d1))
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"""Use script to do all the ABCD and q-parameter math, and return the waist and radius of curvature functions"""
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R, w = bp.q1_inv_func(0, w0, lam, M)
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"""Substitute and extract the required separation between lenses of first 4-f system"""
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distance_between_dmd_first_lens = 250E-3
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first_focal_length = 250.9E-3
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second_focal_length = 50E-3
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demag = 1/5
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target_w0 = demag*w0
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w = w.subs(f1, first_focal_length).subs(f2, second_focal_length).subs(d1, distance_between_dmd_first_lens).subs(d3,0)
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eq = sym.solve(w - target_w0, d2)[0]
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distance_between_lens_of_first_4f = list(eq.atoms())[0]
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print('Distance between lenses of first 4-f system = {} mm'.format(distance_between_lens_of_first_4f * 1E3))
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# Sanity check
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# expansion_factor = w.subs(d2,distance_between_lens_of_first_4f).subs(d3,0)/ w0
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# print('beam is w = {:.2f} x w0'.format(expansion_factor))
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# """Plot beam propagation up to 3 m after the first 4-f system"""
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# M = bp.mult(bp.prop(d3),bp.lens(second_focal_length),bp.prop(distance_between_lens_of_first_4f), bp.lens(first_focal_length), bp.prop(distance_between_dmd_first_lens))
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# R, w = bp.q1_inv_func(0, w0, lam, M)
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# bp.plot(w,d3, rang = np.arange(0,0.050,.0005))
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"""Define the full optical system of two 4-f setups using matrices"""
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d1, d2, d3, d4, f1, f2, f3 = sym.symbols('d1 d2 d3 d4 f1 f2 f3')
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M = bp.mult(bp.prop(d4),bp.lens(f3), bp.prop(d3),bp.lens(f2),bp.prop(d2), bp.lens(f1), bp.prop(d1))
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"""Use script to do all the ABCD and q-parameter math, and return the waist and radius of curvature functions"""
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R, w = bp.q1_inv_func(0, w0, lam, M)
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# """Find the focal length of lens required after the first 4-f system to have a collimated beam, given a certain separation between the first 4-f system and this lens"""
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distance_between_4fs = 550E-3
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R_coll = R.subs(d1,distance_between_dmd_first_lens).subs(d2,distance_between_lens_of_first_4f).subs(d3,distance_between_4fs).subs(d4,0).subs(f1,first_focal_length).subs(f2,second_focal_length)
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f3_coll = sym.solve(1/R_coll,f3)[0]
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third_focal_length = list(f3_coll.atoms())[0]
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print('For a fixed separation between first 4-f and third lens of {:.3f} mm, f3 = {:.3f} mm for a collimated beam'.format(distance_between_4fs* 1E3, third_focal_length * 1E3))
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# # """Plot beam propagation up to 3 m after the first 4-f system"""
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# M = bp.mult(bp.prop(d4),bp.lens(third_focal_length),bp.prop(distance_between_4fs), bp.lens(second_focal_length), bp.prop(distance_between_lens_of_first_4f), bp.lens(first_focal_length), bp.prop(distance_between_dmd_first_lens))
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# R, w = bp.q1_inv_func(0, w0, lam, M)
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# bp.plot(w,d4, rang = np.arange(0,0.050,.0005))
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third_focal_length = 501.8E-3
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R_coll = R.subs(d1,distance_between_dmd_first_lens).subs(d2,distance_between_lens_of_first_4f).subs(d4,0).subs(f1,first_focal_length).subs(f2,second_focal_length).subs(f3,third_focal_length)
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d3_coll = sym.solve(1/R_coll,d3)[1]
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distance_between_4fs = list(d3_coll.atoms())[0]
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print('For a fixed third focal length of {:.3f} mm, d3 = {:.3f} mm, for a collimated beam'.format(third_focal_length* 1E3, distance_between_4fs * 1E3))
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# """Plot beam propagation up to 3 m after the first 4-f system"""
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# M = bp.mult(bp.prop(d4),bp.lens(third_focal_length),bp.prop(distance_between_4fs), bp.lens(second_focal_length), bp.prop(distance_between_lens_of_first_4f), bp.lens(first_focal_length), bp.prop(distance_between_dmd_first_lens))
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# R, w = bp.q1_inv_func(0, w0, lam, M)
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# bp.plot(w,d4, rang = np.arange(0,0.050,.0005))
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