diff --git a/examples/fft/phaseplate.py b/examples/fft/phaseplate.py
new file mode 100644
index 0000000000000000000000000000000000000000..27d860a40508844afc716e90dd35f587500575ff
--- /dev/null
+++ b/examples/fft/phaseplate.py
@@ -0,0 +1,108 @@
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+from __future__ import unicode_literals
+
+import matplotlib.pyplot as plt
+
+from pykat.optics.gaussian_beams import HG_mode, beam_param
+from pykat.optics.fft import *
+import numpy as np
+import scipy
+
+def main():
+ print("""
+ --------------------------------------------------------------
+ Example file for using PyKat http://www.gwoptics.org/pykat
+
+ Generate a HG11 mode from a HG00 mode with a simple
+ phase plate.
+
+ Andreas Freise, 18.10.2016
+ --------------------------------------------------------------
+ """)
+ plt.close('all')
+ # wavelength
+ Lambda = 1064.0E-9
+ # distance to propagate/focal length of lens
+ D = 4
+
+ ######## Generate Grid stucture required for FFT propagation ####
+ xpoints = 512
+ ypoints = 512
+ xsize = 0.05
+ ysize = 0.05
+ # Apply offset such that the center of the beam lies in the
+ # center of a grid tile
+ xoffset = -0.5*xsize/xpoints
+ yoffset = -0.5*ysize/ypoints
+
+ shape = grid(xpoints, ypoints, xsize, ysize, xoffset, yoffset)
+ x = shape.xaxis
+ y = shape.yaxis
+
+ ######## Generates input beam ################
+ gx = beam_param(w0=2e-3, z=0)
+ gy = beam_param(w0=2e-3, z=0)
+ beam = HG_mode(gx,gy,0,0)
+ global field, laser
+ field = beam.Unm(x,y)
+
+ ####### Apply phase plate #######################################
+
+ plate = np.ones([xpoints, ypoints])
+ plate[0:xpoints//2, 0:ypoints//2]=-1.0
+ plate[xpoints//2:xpoints, ypoints//2:ypoints]=-1.0
+
+ field2 = field*plate;
+
+ ####### Propagates the field by FFT ##############################
+ field2 = FFT_propagate(field2,shape,Lambda,D,1)
+
+
+ # maybe apply a thin lens
+ f=D
+ field2 = apply_thin_lens(field2, shape, Lambda, f)
+ field2 = FFT_propagate(field2,shape,Lambda,D,1)
+
+ midx=(xpoints)//2
+ midy=(ypoints)//2
+ off1=50
+ off2=50
+
+ # plot hand tuned for certain ranges and sizes, not automtically scaled
+ fig=plt.figure(110)
+ fig.clear()
+ plt.subplot(1, 3, 1)
+ plt.imshow(abs(field))
+ plt.xlim(midx-off1,midx+off1)
+ plt.ylim(midy-off1,midy+off1)
+ plt.draw()
+ plt.subplot(1, 3, 2)
+ plt.imshow(plate)
+ #pl.xlim(midx-off2,midx+off2)
+ #pl.ylim(midy-off2,midy+off2)
+ plt.draw()
+ plt.subplot(1, 3, 3)
+ plt.imshow(abs(field2))
+ plt.xlim(midx-off2,midx+off2)
+ plt.ylim(midy-off2,midy+off2)
+ plt.draw()
+ if in_ipython():
+ plt.show(block=0)
+ else:
+ plt.show(block=1)
+
+
+# testing if the script is run from within ipython
+def in_ipython():
+ try:
+ __IPYTHON__
+ except NameError:
+ return False
+ else:
+ return True
+
+if __name__ == '__main__':
+ main()
+
diff --git a/examples/fft/spatial_filter.py b/examples/fft/spatial_filter.py
index 1c9e54e8c2fa2b1b13f2b73391157c7c47275dc8..809b10e4163a14feb4da9fa25de71331ec455887 100644
--- a/examples/fft/spatial_filter.py
+++ b/examples/fft/spatial_filter.py
@@ -3,106 +3,119 @@ from __future__ import division
from __future__ import print_function
from __future__ import unicode_literals
-import pylab as pl
+import matplotlib.pyplot as plt
-from pykat.optics.gaussian_beams import HG_beam, beam_param
+from pykat.optics.gaussian_beams import HG_mode, beam_param
from pykat.optics.fft import *
import numpy as np
import scipy
def main():
- # wavelength
- Lambda = 1064.0E-9
- # distance to propagate/focal length of lens
- D = 10
- # mix coefficients
- c1 = 0.7
- c2 = 0.3
- # mode indices
- n1 = 2
- m1 = 3
- n2 = 1
- m2 = 0
-
- ######## Generate Grid stucture required for FFT propagation ####
- xpoints = 512
- ypoints = 512
- xsize = 0.05
- ysize = 0.05
- # Apply offset such that the center of the beam lies in the
- # center of a grid tile
- xoffset = -0.5*xsize/xpoints
- yoffset = -0.5*ysize/ypoints
-
- shape = grid(xpoints, ypoints, xsize, ysize, xoffset, yoffset)
- x = shape.xaxis
- y = shape.yaxis
-
- ######## Generates a mixture of fields ################
- gx = beam_param(w0=2e-3, z=0)
- gy = beam_param(w0=2e-3, z=0)
- beam = HG_beam(gx,gy,n1,m1)
- field1 = beam.Unm(x,y)
- beam2 = HG_beam(gx,gy,n2,m2)
- field2 = beam2.Unm(x,y)
- global field, laser1, laser2
- field = np.sqrt(c1)*field1 + np.sqrt(c2)*field2
+ print("""
+ --------------------------------------------------------------
+ Example file for using PyKat http://www.gwoptics.org/pykat
+
+ Simple spatial filter to measure the mode content in a
+ Hermite Gauss beam
+
+ Andreas Freise, 18.10.2016
+ --------------------------------------------------------------
+ """)
+ plt.close('all')
+
+ # wavelength
+ Lambda = 1064.0E-9
+ # distance to propagate/focal length of lens
+ D = 10
+ # mix coefficients
+ c1 = 0.7
+ c2 = 0.3
+ # mode indices
+ n1 = 2
+ m1 = 3
+ n2 = 1
+ m2 = 0
+
+ ######## Generate Grid stucture required for FFT propagation ####
+ xpoints = 512
+ ypoints = 512
+ xsize = 0.05
+ ysize = 0.05
+ # Apply offset such that the center of the beam lies in the
+ # center of a grid tile
+ xoffset = -0.5*xsize/xpoints
+ yoffset = -0.5*ysize/ypoints
+
+ global shape
+ shape = grid(xpoints, ypoints, xsize, ysize, xoffset, yoffset)
+ x = shape.xaxis
+ y = shape.yaxis
+
+ ######## Generates a mixture of fields ################
+ gx = beam_param(w0=2e-3, z=0)
+ gy = beam_param(w0=2e-3, z=0)
+ beam = HG_mode(gx,gy,n1,m1)
+ field1 = beam.Unm(x,y)
+ beam2 = HG_mode(gx,gy,n2,m2)
+ field2 = beam2.Unm(x,y)
+ global field, laser1, laser2
+ field = np.sqrt(c1)*field1 + np.sqrt(c2)*field2
- ####### Apply phase plate #######################################
-
- laser1 = field*(np.conjugate(field1))
- laser2 = field*(np.conjugate(field2))
-
- ####### Propagates the field by FFT ##############################
- laser1 = FFT_propagate(laser1,shape,Lambda,D,1)
- laser2 = FFT_propagate(laser2,shape,Lambda,D,1)
-
- f=D
- #laser1 = apply_lens(laser1, shape, Lambda, f)
- #laser2 = apply_lens(laser2, shape, Lambda, f)
- laser1 = apply_thin_lens(laser1, shape, Lambda, f)
- laser2 = apply_thin_lens(laser2, shape, Lambda, f)
-
- laser1 = FFT_propagate(laser1,shape,Lambda,D,1)
- laser2 = FFT_propagate(laser2,shape,Lambda,D,1)
-
- # midpoint computation for even number of points only!
- midx=(xpoints)//2
- midy=(ypoints)//2
- coef1 = np.abs(laser1[midx,midy])
- coef2 = np.abs(laser2[midx,midy])
-
- ratio = (coef1/coef2)**2
- pc2 = 1/(1+ratio)
- pc1 = pc2*ratio
-
- print("c1 {0}, coef1 {1}, error {3} (raw output {2})".format(c1, pc1, coef1, np.abs(c1-pc1)))
- print("c2 {0}, coef2 {1}, error {3} (raw output {2})".format(c2, pc2, coef2, np.abs(c2-pc2)))
-
- # plot hand tuned for certain ranges and sizes, not automtically scaled
- fig=pl.figure(110)
- fig.clear()
- off1=xpoints/10
- off2=xpoints/6
- pl.subplot(1, 3, 1)
- pl.imshow(abs(field))
- pl.xlim(midx-off1,midx+off1)
- pl.ylim(midy-off1,midy+off1)
- pl.draw()
- pl.subplot(1, 3, 2)
- pl.imshow(abs(laser1))
- pl.xlim(midx-off2,midx+off2)
- pl.ylim(midy-off2,midy+off2)
- pl.draw()
- pl.subplot(1, 3, 3)
- pl.imshow(abs(laser2))
- pl.xlim(midx-off2,midx+off2)
- pl.ylim(midy-off2,midy+off2)
- pl.draw()
- if in_ipython():
- pl.show(block=0)
- else:
- pl.show(block=1)
+ ####### Apply phase plate #######################################
+
+ laser1 = field*(np.conjugate(field1))
+ laser2 = field*(np.conjugate(field2))
+
+ ####### Propagates the field by FFT ##############################
+ laser1 = FFT_propagate(laser1,shape,Lambda,D,1)
+ laser2 = FFT_propagate(laser2,shape,Lambda,D,1)
+
+ f=D
+ #laser1 = apply_lens(laser1, shape, Lambda, f)
+ #laser2 = apply_lens(laser2, shape, Lambda, f)
+ laser1 = apply_thin_lens(laser1, shape, Lambda, f)
+ laser2 = apply_thin_lens(laser2, shape, Lambda, f)
+
+ laser1 = FFT_propagate(laser1,shape,Lambda,D,1)
+ laser2 = FFT_propagate(laser2,shape,Lambda,D,1)
+
+ # midpoint computation for even number of points only!
+ midx=(xpoints)//2
+ midy=(ypoints)//2
+ coef1 = np.abs(laser1[midx,midy])
+ coef2 = np.abs(laser2[midx,midy])
+
+ ratio = (coef1/coef2)**2
+ pc2 = 1/(1+ratio)
+ pc1 = pc2*ratio
+
+ print("c1 {0}, coef1 {1}, error {3} (raw output {2})".format(c1, pc1, coef1, np.abs(c1-pc1)))
+ print("c2 {0}, coef2 {1}, error {3} (raw output {2})".format(c2, pc2, coef2, np.abs(c2-pc2)))
+
+ # plot hand tuned for certain ranges and sizes, not automtically scaled
+ fig=plt.figure(110)
+ fig.clear()
+ off1=xpoints/10
+ off2=xpoints/6
+ plt.subplot(1, 3, 1)
+ plt.imshow(abs(field))
+ plt.xlim(midx-off1,midx+off1)
+ plt.ylim(midy-off1,midy+off1)
+ plt.draw()
+ plt.subplot(1, 3, 2)
+ plt.imshow(abs(laser1))
+ plt.xlim(midx-off2,midx+off2)
+ plt.ylim(midy-off2,midy+off2)
+ plt.draw()
+ plt.subplot(1, 3, 3)
+ plt.imshow(abs(laser2))
+ plt.xlim(midx-off2,midx+off2)
+ plt.ylim(midy-off2,midy+off2)
+ plt.draw()
+ if in_ipython():
+ plt.show(block=0)
+ else:
+ plt.show(block=1)
# testing if the script is run from within ipython
@@ -115,5 +128,5 @@ def in_ipython():
return True
if __name__ == '__main__':
- main()
+ main()