Add depth_max keyword to solve_system!

[TacHawkes]

This small PR adds a new keyword depth_max to the solve_system! function in order to solve #40 This depth limits the max branching depth of a beam.

This is useful to set when tracing resonant elements like resonators or filter cavities.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 71.60%. Comparing base (16cecf8) to head (5be22f7).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #41      +/-   ##
==========================================
+ Coverage   71.57%   71.60%   +0.02%     
==========================================
  Files          57       57              
  Lines        2881     2884       +3     
==========================================
+ Hits         2062     2065       +3     
  Misses        819      819              

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[TacHawkes]

Setting the keyword recovers the performance. It is up to the user to set depth_max to achieve the desired precision when simulating a resonant elements.

Example:

using GLMakie, BeamletOptics

GLMakie.activate!(; ssao=true)
const BMO = BeamletOptics

const mm = 1e-3

mirror_diameter = 25mm
cavity_length = 12mm
reflectance = 0.92
detector_offset = 70mm

input_wavelength = 632.8e-9
input_waist = 0.04mm

mirror1 = RoundThinBeamsplitter(mirror_diameter; reflectance)
mirror2 = RoundThinBeamsplitter(mirror_diameter; reflectance)

translate3d!(mirror2, [0, cavity_length, 0])

detector = Detector(40mm)
translate3d!(detector, [0, cavity_length + detector_offset, 0])

system = StaticSystem([mirror1, mirror2, detector])

beam = GaussianBeamlet([0, -detector_offset, 0], [0, 1, 0], input_wavelength, input_waist)

empty!(detector)
solve_system!(system, beam, depth_max=100)

##
x, z, I = intensity(detector; n=400, crop_factor=1.0)

##
fig = Figure(size=(720, 540))
ax = Axis(fig[1, 1]; aspect=DataAspect(), xlabel="x (mm)", ylabel="z (mm)")
hm = heatmap!(ax, x ./ mm, z ./ mm, log10.(I .+ eps()))
colorbar = Colorbar(fig[1, 2], hm, label="Intensity (a.u.)")

fig