This calculator evaluates spot size of Gaussian beam focused by an aberration free lens. Enter required data into the boxes to calculate focused spot size diameter and Rayleigh range for your measurement. You might get to know required parameters by fallowing below provided tutorial.
1. Considering an optical system in air lens focal length is the distance over which initially collimated rays are brought to a focus. It is basic description of the lens and usually provided by the production. However, you should note that focus length of the same lens differs for different wavelengths.
2. In physics, the wavelength λ of the sinusoidal wave is the spatial period of the wave - the distance over which the wave's shape repeats.
3. M² is the beam quality factor. It provides a simple means for accurately calculating the most commonly required parameters of real world laser beams, namely, divergence angle, propagation characteristics over a distance, and the size of focused spots.
4. Spot size diameter (marked as DL in the figure) is the diameter of the beam spot size at the I0/e² level of intensity on the entrance of the lens.
5. Focused spot size (marked as Dwaist in the figure) is the diameter of the focused spot size at the I0/e² level of intensity. It is calculated as:
6. Rayleigh range
(marked as zR
in the figure) is a very common and useful beam metric. It defines distance over which the beam diameter increases by a factor of
, and its cross sectional area doubles. It is calculated as: