Calculate expansion ratio, output diameter, and reduced divergence.
Expander Parameters
mm
mm
mm
mrad
Output Results
Enter parameters to calculate expansion
About this calculator
Quick Reference
MMagnification / Expansion Ratio
f₁/f₂Focal lengths of lenses
DBeam diameter
θDivergence angle
Overview
A laser beam expander is used to increase the diameter of a laser beam. This process simultaneously reduces the beam's divergence, making it more 'collimated' over long distances.
💡
Pro Tips
The expansion ratio M is the ratio of output diameter to input diameter.
Increasing the beam diameter by M decreases the divergence angle by 1/M.
Keplerian expanders use two positive lenses, while Galilean expanders use one positive and one negative lens.
!
Fun Facts
"Wait, did you know that expanding a beam to twice its size actually makes it stay tighter for longer? It sounds counterintuitive, but physics wins again!"
"Most high-power lasers use beam expanders to reduce the power density on downstream optical components, preventing damage."
"Galilean beam expanders are shorter and don't have an internal focal point, which is better for high-power lasers that might ionize the air."
Formula: M = f₂ / f₁, D_out = M * D_in, θ_out = θ_in / M
