Laser Spot Size Calculator
Determine the diffraction-limited spot size when a laser beam is focused by a lens. Calculates spot diameter, depth of focus (Rayleigh range), peak intensity, and f-number of the focusing system.
Inputs
1/e² diameter of the collimated beam
CW power or average power for peak intensity calculation
Results
Spot Diameter
27.1 μm
Depth of Focus
1.08 mm
Peak Intensity
346.9 kW/cm²
Laser Spot Size Results
| Parameter | Value |
|---|---|
| Spot Diameter (1/e²) | 27.09 μm |
| Spot Radius w₀ | 13.55 μm |
| Depth of Focus (2×z_R) | 1.0838 mm |
| Peak Intensity I₀ | 346.88 kW/cm² |
| f-Number | f/20.00 |
| Numerical Aperture | 0.0250 |
| M² Factor | 1 |
| Input Beam Diameter | 5 mm |
| Focal Length | 100 mm |
| Formula | d = 4M²λf/(πD) |
Frequently Asked Questions
Related Calculators
Gaussian Beam Calculator
Calculate Rayleigh range, divergence angle, beam diameter at distance, and depth of focus for a Gaussian beam.
Angular Resolution Calculator
Calculate the diffraction-limited angular resolution using the Rayleigh criterion θ = 1.22λ/D.
NA to f-Number Converter
Convert between Numerical Aperture (NA) and f-number. NA = 1/(2×f/#) for small angles, or NA = n×sin(θ).