57 lines
1.7 KiB
Python
57 lines
1.7 KiB
Python
# These calculations are based on Ashkin's article "Forces of a single-beam
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# gradient laser trap on a dielectric sphere in the ray optics regime".
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# There are transverse forces only
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import numpy as np
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import matplotlib.pyplot as plt
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import seaborn as sns
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from functions import *
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sns.set()
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# Intensity profile graphics
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rho = np.linspace(-r_max, r_max, 500)
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fig1 = plt.figure(1, figsize=(10, 6))
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I = gauss(rho)
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I0 = np.max(I)
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plt.plot(rho, I / I0)
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plt.fill_between(rho, I / I0, 0, alpha=0.3)
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plt.xlabel('r, m', fontsize=18)
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plt.ylabel('I(r)', fontsize=18)
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# Integration
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def q_res_g(dy, func):
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ans = integrate.dblquad(lambda dr, db, dy: dr * func(dr) * q_g_y(db, dr, dy) * (~np.iscomplex(q_g_y(db, dr, dy))).astype(float),
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0, 2 * np.pi, 0, r_max, args=(dy, ),
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epsabs=1e-8, epsrel=1e-6)
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return ans[0]
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def q_res_s(dy, func):
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ans = integrate.dblquad(lambda dr, db: dr * func(dr) * q_s_y(db, dr, dy) * (~np.iscomplex(q_g_y(db, dr, dy))).astype(float),
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0, 2 * np.pi, 0, r_max,
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epsabs=1e-8, epsrel=1e-6)
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return ans[0]
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# Calculation
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n = 150
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y = np.linspace(-2 * Rsp, 2 * Rsp, n)
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transverse_g = gauss_peak() * F0 * np.abs(np.array([q_res_g(x, gauss) for x in y]))
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transverse_s = gauss_peak() * F0 * np.array([q_res_s(x, gauss) for x in y])
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transverse = transverse_g + transverse_s
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# Graphics
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fig2 = plt.figure(2, figsize=(10, 6))
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plt.plot(y, transverse_g, '-.', lw=1, label='$F_{g}$')
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plt.plot(y, transverse_s, '--', lw=1, label='$F_{s}$')
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plt.plot(y, transverse, lw=1, label='$F_{t}$')
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plt.xlabel('r, m', fontsize=18)
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plt.ylabel('F, m', fontsize=18)
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plt.legend()
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plt.show() |