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--- ao:lab_ao [2018/07/07 09:29]
jones
+++ ao:lab_ao [2018/07/07 09:49]
jones
@@ Line 11: / Line 11: @@
   * After e.g. 300mm, the beam hits the dichroic.
   * After e.g. 300mm, the beam hits the LDC
-The thin-lens formula simple script that Mike used to make these calculations is {{ao:chara_ao_calcs.py|chara_ao_calcs.py}}\\
+The thin-lens formula simple python script that Mike used to make these calculations is
+  import numpy as np
-  * [[/file/detail/chara_ao_calcs.py|Details]]
+  import matplotlib.pyplot as plt
-  * [[/file/view/chara_ao_calcs.py/478648308/chara_ao_calcs.py|Download]]
-  * 1 KB
+  f1 = 1280.
-.\\ \\  The wavefront sensor could be built around the 18-00079 microlens array from SUSS - 53 Euro each. These have a 30 micron pitch, meaning that with a 5 lenslet sampling across the pupil (19 lenslets altogether), the desired pupil size is 0.15mm. If there aren't enough of these in stock (SUSS are now listing these as a discontinued product), a microlens array with a different geometry may be needed. It is critical to have no more than about (focal length) * lambda * 20 > pitch^2, in order to not take up too many pixels. So an alternative is [[http://www.suss-microoptics.com/shop/microlens-arrays/fused-silica/square-lenses/microlens-array-nr-18-00216.html|18-00216]]. The catch is that this is a 10mm x 10mm piece, which ideally we'd want to be diced up.\\ \\  The key is that with 3 lenses plus the microlens array, there isn't that much sensitivity loss (it is a slow wavefront sensor) and with catalog parts we can be flexible.\\ \\  After the beamsplitter, towards the wavefront sensor, we need for the 30 micron pitch version:\\
+  f2 = 192.
+  dz = 22.9#15 + np.arange(200)/10.
+  sep = f1 - f2 + dz
+  smallpsize=19.0
+  # focus_from_secondary
+  ffs = 1.0/(1.0/(f2-dz) - 1.0/f2)
+  #pupil distance (in mm)
+  pd = 200000.
+  #pupil distance to secondary
+  pds =  1.0/(1.0/f1 - 1.0/pd) - (f1 - f2 + dz)
+  #pupil image from secondary:
+  pfs = 1/(1/pds - 1/f2)
+  psize = smallpsize*(f2-dz)/f2*(pfs-ffs)/ffs
+  #19mm collimator from pupil
+  frat = ffs/(smallpsize*(f2-dz)/f2)
+  colfs = ffs + smallpsize*frat
+  colfdm = colfs - pfs
+  #plt.plot(pfs,psize)
+\\  The wavefront sensor could be built around the 18-00079 microlens array from SUSS - 53 Euro each. These have a 30 micron pitch, meaning that with a 5 lenslet sampling across the pupil (19 lenslets altogether), the desired pupil size is 0.15mm. If there aren't enough of these in stock (SUSS are now listing these as a discontinued product), a microlens array with a different geometry may be needed. It is critical to have no more than about (focal length) * lambda * 20 > pitch^2, in order to not take up too many pixels. So an alternative is [[http://www.suss-microoptics.com/shop/microlens-arrays/fused-silica/square-lenses/microlens-array-nr-18-00216.html|18-00216]]. The catch is that this is a 10mm x 10mm piece, which ideally we'd want to be diced up.\\ \\  The key is that with 3 lenses plus the microlens array, there isn't that much sensitivity loss (it is a slow wavefront sensor) and with catalog parts we can be flexible.\\ \\  After the beamsplitter, towards the wavefront sensor, we need for the 30 micron pitch version:\\
   * A 25mm diameter, 150mm focal-length achromat that forms a new pupil image.

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