[xx, yy] = meshgrid(x, y)
lg = lg.LG_xy(l=l, p=0, xx=xx, yy=yy, omega0=2 / sqrt(l))
# normalize lg; we only want the phase information
lg /= abs(lg)
#imshow (x,y,arg(lg))
####### END Create LG order
propagate = Propagate()
if False:
##### Just the hollow beam relayed.
F = Field(N, side_length, wavelength) # beginning field
F.gaussian_aperture(gaussian_size)
F.value[:] *= lg # SLM LG phase
F.lens(fslm) # 'SLM' lens
F.forvard(fslmR)
F.lens(fslmR) # relay:1 lens:1
F.forvard(2 * fslmR)
F.lens(fslmR) # relay:1 lens:2
F.forvard(fslmR + fslm) # MOT (1st pass)
imshow((F.value * F.value.conj()).real)
print 'press enter to continue'
raw_input()
F.forvard(fr1)
F.lens(fr1, ) # relay:2 lens:1
F.forvard(fr1 + fr2)
F.lens(fr2, ) # relay:2 lens:2
F.forvard(2 * fr2)
wavelength = 780 * nm # Wavelength
gaussian_size = 1.00 / sqrt(
2) * mm # 1/e Intensity width of beam; (note, it's not the 1/e^2)
step_size = 5. * mm # LPForvard step size
f = 20 * cm # focal length of SLM lens
l = 8 # azimuthal order of LG beam
######## END Param ##############
####### Create LG order
dx = (2 / (N - 1.))
x = y = 3 * r_[-1:(1 + dx):dx]
[xx, yy] = meshgrid(x, y)
lg = lg.LG_xy(l=l, p=0, xx=xx, yy=yy, omega0=2 / sqrt(l))
# normalize lg; we only want the phase information
lg /= abs(lg)
#imshow (x,y,arg(lg))
####### END Create LG order
propagate = Propagate()
F = Field(N, side_length, wavelength)
F.gaussian_aperture(gaussian_size)
F.lens(f)
F.value[:] *= lg
propagate(F, z=f + cm, dz=.5 * cm)
#F.forvard(18.0*cm)
#F5 = propagate(4.*cm,.5*cm, F4,0,0,4)
#F5 = propagate(13.*cm, step_size, F4,0,0,4)
lg /= abs(lg) #imshow (x,y,angle(lg)) ####### END Create LG order propagate = Propagate() F = Field(N, side_length, wavelength) F.gaussian_aperture(gaussian_size) Pf = P / sum(F.value * F.value.conj()) # power per grid cell [ W ] Ef = sqrt(Pf / grid_dx**2) # sqrt(I) [ sqrt(W/m^2) ] Ef /= sqrt(mW / cm**2) # put Ef in units [ sqrt(mW/cm^2) ] F.value[:] *= Ef # put F in units of sqrt(I) print 'writing SLM phase...' F.lens(f) # apply lens (physical lens) Fb = F.copy() # store the undeflected beam Fb.value[:] *= sqrt(0.2) # undeflected light F.value[:] *= lg # apply lg phase grating.phase.perfect(F, 32, 0) # apply a perfect grating phase. F.value[:] *= sqrt(0.8) # deflection efficiency of SLM F.value[:] += Fb.value # mix the beams back together. print 'finished writing SLM phase.' F.forvard(lf * f) # traverse a piece of glass and interfere primary beam with 1st internally # reflected+transmitted beam. Fr = F.copy() Fr.interpolate(side_length, N, dx0) Fr.value[:] *= exp(1j * dphi) # add phase delay to secondary beam
#!/usr/bin/env python """ LightPipes for Python Optical Toolbox Calculates the Fraunhofer diffraction of a round hole. """ import common from lightpipes import Field from pylab import * m = 1 nm = 1e-9 * m mm = 1e-3 * m cm = 1e-2 * m wavelength = 1000 * nm size = 10 * cm N = 150 R = 10 * mm z = 1000 * m f1 = 200 * m f2 = -200 * m F = Field(N, size, wavelength) F.circular_aperture(R) F.lens(f1) F.lens_forvard(f2, z) imshow(abs(F.value)**2) # plot intensity show()
#imshow (x,y,arg(lg)) ####### END Create LG order propagate = Propagate() F = Field(N, side_length, wavelength) F.gaussian_aperture(gaussian_size) F.axicon(axicon_angle, axicon_n1) #propagate(F, z=13.*cm, dz=step_size) F.forvard(7.5 * cm) F.axicon(axicon_angle, axicon_n1) print 'moving towards slm' #F.forvard(40*cm) propagate(F, z=75. * cm, dz=5 * cm) print 'first lens' F.lens(-75 * cm) propagate(F, z=100. * cm, dz=5 * cm) print 'second lens' F.lens(-25 * cm) propagate(F, z=25. * cm, dz=1 * cm) print 'applying slm' F.value[:] *= lg propagate(F, z=50. * cm, dz=2 * cm) print 'press enter to exit' raw_input()
