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Ray Tracing
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Ray tracing is a method to simulate the propagation of electromagnetic waves
according to geometric optics, which is the approximation of wave optics theory when
wavelength is small enough.


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Ray Tracing based Optical Systems
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TODO

.. _guide_optics_rt_lcs:

Lens' coordinate system
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TODO

.. _guide_optics_rt_slcs:

Surface-local coordinate system
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TODO