omega0_p = .5
######## 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) ) \
+ lg.LG_xy( l=0, p=p, xx=xx, yy=yy, omega0=.85*2/sqrt(l) )
# normalize lg; we only want the phase information
lg /= abs(lg)
#imshow (angle(lg)); show()
####### END Create LG order
propagate = Propagate(vmin=0., vmax=100.)
F = Field(N, side_length, wavelength)
F.gaussian_aperture(gaussian_size)
#F.lens(f)
F.value[:] *= lg
#propagate(F, z=2*f, dz=.5*cm)
for z in r_[0:(2 * f):(.1 * f)]:
Fcopy = F.copy()
Fcopy.lens_forvard(f, z)
propagate.imshow((Fcopy.value * Fcopy.value.conj()).real)
raw_input()
l = 2 # 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.axicon(axicon_angle, axicon_n1) #F4 = propagate(13.*cm, step_size, F3,0,0,4); F.forvard(7.5 * cm) F.axicon(axicon_angle, axicon_n1) print 'moving towards slm' #F.forvard(40*cm) propagate(F, z=40. * cm, dz=10 * cm) print 'applying slm' F.value[:] *= lg propagate(F, z=50. * cm, dz=2 * cm)
the toroidal lens at the SLM. """ phi = zeros(x.shape) r2 = x**2 + y**2 Ri_2 = (R - 0.5*w)**2 Rf_2 = (R + 0.5*w)**2 phi[ nonzero( r2 < Rf_2 ) ] = pi phi[ nonzero( r2 < Ri_2 ) ] = 0 return phi x = y = grid_dx * r_[-255.5:256:1.] [xx, yy] = meshgrid(x,y) torus_phase = tlens(xx,yy,R0,f_torus,wavelength) + phase_ring(xx,yy,R1,w1) propagate = Propagate() #print 'press enter to continue' #propagate.imshow( torus_phase ) #raw_input() # propagate the field from the SLM and take a look F = Field( N, side_length, wavelength) # initial field F.gaussian_aperture(w) # gaussian input F.circular_aperture(side_length/2.) # Iris in front of SLM F.value[:] *= exp(1j * torus_phase ) # apply SLM phase F.forvard(f_torus) propagate(F, z=f_torus, dz=f_torus/25.) print 'press enter to show final phase...' raw_input()