Laser Focusability (Gaussian Beam)

For a collimated beam, the diffraction-limited focal spot size of a laser beam depends on its wavelength, the size of the beam at the lens and its M2 value. Use this simple calculator to determine your laser's diffraction-limited focal spot size, assuming an ideal lens without aberrations and a collimated laser beam. If the beam is not collimated, then the full Focal Spot Size Calculator should be used (set p to 0.01 and fill in λ, fl, θ, d).




 Laser Focusability (Gaussian Beam)

Wavelength

(nm) *

Lens focal length

(mm) *

Beam diameter (at lens)

This is the 1/e2 diameter of the Gaussian beam. It's the point at which the power is about 13.5% of the peak power.

(mm) *

M-Squared

*