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fourierOptics/demonstration scripts/generate_bahtinov_dispersion.py

81 lines
2.8 KiB
Python

import numpy as np
import sys
sys.path.insert(0, '/Users/joost/Dropbox/Werk/PhD/Documents/Published/FourierOptics GitHub release/')
from fourierOptics import *
'''
Description:
This script generates a point spread function of the MICADO optical model.
Here we apply a Bahtinov mask to the pupil and simulate a broadband PSF,
done through the summation of multiple (here: 15) wavelength slices.
When there is atmospheric dispersion, the diffraction speckles created by the
Bahtinov mask will start to point to a location outside the zeroth order
PSF core.
Here, atmospheric dispersion is modelled as a wavelength dependent phase
tilt.
'''
if __name__ == '__main__':
# Initiate MICADO paraxial model
mcd = ParaxialMICADO()
wfe = WavefrontError(mcd.n, mcd.m)
# Create the Bahtinov mask and set it on the entrance pupil (ELT-M1)
bahtinov = Profiles().bahtinov_mask(40, 10, mcd.n, mcd.m, dpix=0.33, N=30, oversample=1)
mcd.ELT_CAM.add_mask(bahtinov)
# Set up
Elist = []
lList = np.linspace(1.49e-3, 1.78e-3, 15).tolist()
# Dispersion of 40 mas over the band
dispMax = 40e-3 / 3600 # maximum dispersion in degrees
dispersion = np.linspace(0, dispMax, len(lList)).tolist()
# Iterate over the wavelengths
for i in range(len(lList)):
l = lList[i]
# Generating the tilt to the input field.
d = dispersion[i]
field_tilt = wfe.generate_tilt(mcd.x,mcd.y,tx=0, ty=d)
# Adding the tilt to the input field
Ein = Profiles().ELT_pupil(mcd.n,mcd.m,mcd.dpix).astype('complex128')\
* np.exp(-1j * 2*np.pi/l * field_tilt)
mcd.apply_mask(Ein, replace=True)
# Propagate the input field throug the paraxial model
E, x, y = mcd.propagate(l=l,surface=-1, zoom=False, show=False,
image_output=[-4,4,-4,4], print_progress=True)
Elist.append(E)
# Average over all the wavelengths to get the final field.
Eca = np.asarray([np.abs(x) for x in Elist]).mean(axis=0) # Amplitude
Eci = Eca**2 # Intensity
Ecp = np.asarray([np.angle(x) for x in Elist]).mean(axis=0) # Phase
# Convert the scale to sky-angles using the plate scale
x *= mcd.platescale*1000 # x in milli arcseconds
y *= mcd.platescale*1000 # y in milli arcseconds
# Plotting the results
fig = plt.figure(figsize=(8,3))
ax = fig.add_subplot(121)
im = ax.imshow(Eca, cmap='hot', origin='lower', extent=[x.min(),x.max(),y.min(),y.max()])
ax.set_xlim([x.min(),x.max()])
ax.set_ylim([y.min(),y.max()])
ax.set_xlabel('x [mas]')
ax.set_ylabel('y [mas]')
fig.colorbar(im, ax=ax, label='Amplitude')
ax2 = fig.add_subplot(122)
im2 = ax2.imshow(Ecp, cmap='hot', origin='lower', extent=[x.min(),x.max(),y.min(),y.max()])
ax2.set_xlim([x.min(),x.max()])
ax2.set_ylim([y.min(),y.max()])
ax2.set_xlabel('x [mas]')
ax2.set_ylabel('y [mas]')
fig.colorbar(im2, ax=ax2, label='Phase')
plt.tight_layout()
plt.show()