Tracing

• Paraxial equation and equation of motion are 2nd order ordinary differential equations
• They differ in just having z (for paraxial trajectory equation) or t (for ray tracing) as an independent variable
• “Standard” Runge-Kutta variable step methods can be used (order 4-5 in z and 7-8 in t)
• Large meshes and accurate 2D interpolation methods allow also fast ray tracing with high accuracy
• It is possible to use 2D plot in EOD to fit linear, parabolic or cubic polynomial for getting selected aberrations