openphoton 0.1.4

A scalar diffraction simulation package

openphoton

The latest version allows you to simulate light propagation from a laser, passing through lens, and passing through your test object. More features will be added soon.

Examples of How To Use (Alpha Version)

Add openphoton to your operating system or python virtual environment :

pip install openphoton

Create a laser beam :

import openphoton as op

# side length (m)
# aperture radius (m)
u0 = op.devices.laser_beam(
    side_length=0.06,
    aperture_radius=0.026,
    pixels=1024)

In order to forward propagate the wave field, you must choose between fresnel (near-field) approximation and fraunhoffer (far-field) approximation. To determine which approximation is best for your system, you have to calculate the Fresnel number F_N. If F_N = [1, +infinity], then use fresnel approximation. Otherwise, use fraunhoffer approximation.

# uo = wave field to propagate
# L = source plane side length (m)
# wavelength = wavelength of light (m)
# z = propagation distance (m)
# u1 = resulting wave field after propagation
u1 = op.rayleigh_sommerfeld.fresnel_approx(
    u0, L, wavelength, z)

Apply converging lens or diverging lens on the laser beam :

import numpy as np

# u1 = wave field before the lens
# L = u1 side length (m)
# wavelength of light (m)
# f_length = lens focal length (m)
# u2 = wave field after the lens
u2 = np.multiply(u1, op.lenses.converging_lens(u1,L,wavelength,f_length))

Apply SLM or test object on the laser beam :

import numpy as np

# filename = image of test object file name
filename : str = "USAF_1951_1024p.png"

# SLM_amplitude() converts RGB image into numpy array
# pixel_size = number of pixels of image, ideally this must be the same with u1
test_object = op.devices.SLM_amplitude(filename, pixel_size)

# u1 = wave field before the test object
# L = u1 side length (m)
# wavelength of light (m)
# u2 = wave field after the test object
u2 = np.multiply(u1, test_object)

References:

• Shen, Fabin, and Anbo Wang. "Fast-Fourier-transform based numerical integration method for the Rayleigh-Sommerfeld diffraction formula." Applied optics 45, no. 6 (2006): 1102-1110.
• Schmidt, Jason D. "Numerical simulation of optical wave propagation with examples in MATLAB." SPIE (2010).
• Voelz, David G., and Michael C. Roggemann. "Digital simulation of scalar optical diffraction: revisiting chirp function sampling criteria and consequences." Applied optics 48, no. 32 (2009): 6132-6142.

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