|Spot Size||Represents the resulting geometrical spot size after the beam has exited the lens|
|db||Represents the diameter of the beam that enters the lens (units are in mm)|
|f||Represents the focal length of the lensxRepresents the propagation distance from the output side of the lens to the illuminated spot|
Note: if f<0, be sure type in a negative sign into a calculator.
Determine the illuminated spot size resulting from a collimated light source passing through a singlet based on the input beam diameter, the lens focal length, and the propagation distance. Calculator assumes a thin lens and uses the paraxial approximation. The calculator works for three possible scenarios: f > 0 and the propagation distance > f, f > 0 and the propagation distance < f, and f < 0. The larger the difference between propagation distance and focal length the greater the spot size will be.