Beam Quality Factor Calculator

The Beam Quality Factor (BQF), also known as M², is a parameter that characterizes the quality of a laser beam. It indicates how well the beam is focused compared to an ideal Gaussian beam. A lower M² value means a better focused beam.

Input Parameters

Calculation Results

Calculation Formula

M² = (wL / w₀) * (L / π)

Where:
M² = Beam Quality Factor
w₀ = Beam waist radius at the focal point
wL = Beam radius at distance L from the waist
L = Distance from the waist to the measurement point

Beam Quality Factor Calculator Usage Guide

Learn how to use the Beam Quality Factor Calculator and its working principles

How to Use This Calculator

  1. Enter the Beam Waist Radius (w₀) in millimeters (mm).
  2. Enter the Distance from the Waist (L) in millimeters (mm).
  3. Enter the Beam Radius at L (wL) in millimeters (mm).
  4. Click the "Calculate" button to compute the Beam Quality Factor (M²).
  5. The result will be displayed in the M² field.

Understanding the Beam Quality Factor (M²)

The Beam Quality Factor (M²) is a dimensionless parameter that describes how well a laser beam is focused. It compares the actual beam to an ideal Gaussian beam with the same waist size. The theoretical value for an ideal Gaussian beam is M² = 1.0.

A higher M² value indicates a beam that spreads more quickly and is less focused, while a lower M² value indicates a beam that is more tightly focused.

Example

If a laser beam has a waist radius (w₀) of 1.0 mm, and at a distance of 100 mm from the waist, the beam radius (wL) is measured to be 2.5 mm, the Beam Quality Factor (M²) can be calculated as:

M² = (2.5 mm / 1.0 mm) * (100 mm / π) ≈ 7.96

This indicates that the beam is less focused than an ideal Gaussian beam.