pygrin

pygrin

by Scott Prahl

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A basic collection of routines to ray trace through graded index (GRIN) lenses with a parabolic radial profile.

.. image:: https://raw.githubusercontent.com/scottprahl/pygrin/master/docs/pitch.png :alt: full pitch lens

Example

Properties of a 0.25 pitch GRIN lens from an ancient Melles Griot Catalog::

import pygrin
n = 1.608 
gradient = 0.339 
length = 5.37
diameter = 1.8

pitch = pygrin.period(gradient, length)
ffl = pygrin.FFL(n,pitch,length)
efl = pygrin.EFL(n,pitch,length)
na = pygrin.NA(n,pitch,length,diameter)

angle = pygrin.max_angle(n,pitch,length,diameter)
print('expected pitch = 0.29,            calculated %.2f' % pitch)
print('expected FFL = 0.46 mm,           calculated %.2f' % ffl)
print('expected NA = 0.46,               calculated %.2f' % na)
print('expected full accept angle = 55°, calculated %.0f°' % (2*angle*180/np.pi))
print('working distance = %.2f mm'%(efl-ffl))

Produces::

expected pitch = 0.29,            calculated 0.29
expected FFL = 0.46,              calculated 0.47
expected NA = 0.46,               calculated 0.46
expected full accept angle = 55°, calculated 55°
working distance = 1.43 mm

But the real utility of this module is creating plots that show the path of rays through a GRIN lens. For examples, see https://pygrin.readthedocs.io

Installation

Use pip::

pip install pygrin

or conda::

conda install -c conda-forge pygrin

or use immediately by clicking the Google Colaboratory button below

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License

pygrin is licensed under the terms of the MIT license.