Seeing convergence within 100 iterations for near-concentric resonator only for very small aperture.

Reworked GaussianBeam class to use @property. Beam decomposition after M2 lens now found by using ABCD matrix and accounting for Gouy phase shift of Laguerre-Gauss modes.

Added Jupyter notebook calculating M2 measurement of laser beam with spherical aberrations using explicit integration, POP (with poppy), and mode decomposition.

Added conversion of focal length of additional length into change in distance between fiber and collimator.

Updated „Doppler shift simulation to 2S-6P OBEs. Rewrote management of various electric fields. Updated plots of OBE results.

Started using LightPipes module. Added script to estimate influence of lens imperfections on standing wave pattern relevant for light force shift.

(sampling of diffracted electric field was very low, introduced with
automatic determination of delta)

Added some additional simulations for older designs
	Added effect of reflection off lens surfaces