What is laser beam quality M2?
What is laser beam quality M2?
In laser science, the parameter M2, also known as the beam propagation ratio or beam quality factor is a measure of laser beam quality. It represents the degree of variation of a beam from an ideal Gaussian beam. It relates the beam divergence of a laser beam to the minimum focussed spot size that can be achieved.
How is laser beam quality measured?
For laser beams for which the second-order moments of intensity (beam width) and divergence can be determined, the beam-propagation ratio M2 is often used to characterize beam quality. The M2 factor compares the actual shape of the beam to that of an ideal Gaussian beam.
What is the M2 factor?
M2 factor is known as the beam quality factor and it represents the degree of variation of a laser beam from an ideal Gaussian beam. It determines how well a laser beam will focus or diverge. According to ISO 11146-1, M2 is defined as BPP (Beam Parameter Product) divided by λ/π.
What is mode quality?
2. ) Measurement Improves Laser Performance. The laser mode quality factor (M2) provides a highly useful means of predicting laser beam propagation and focusing characteristics for both laser manufacturers and systems integrators.
What is the beam quality M2 factor for an ideal beam?
A diffraction-limited beam has an M2 factor of 1, and is a Gaussian beam. Smaller values of M2 are physically not possible. A Hermite–Gaussian beam, related to a TEMnm resonator mode, has an M2 factor of (2n + 1) in the x direction, and (2m + 1) in the y direction [1].
How are M Squared Lasers measured?
Measuring M-squared Factor
- Start with a collimated beam.
- Focus it with an aberration-free lens.
- Measure the diameter of the beam at various positions around the focal point: take at least 10 data points, approximately half within the first Rayleigh distance of the focal point, and the other half beyond 2 Rayleigh lengths.
How is M2 laser measured?
M2 is measured on real beams by focusing the beam with a fixed position lens of known focal length, and then measuring the characteristics of the artificially created beam waist and divergence.
How do you find the quality of a beam?
The most common ways to quantify the beam quality are: the beam parameter product (BPP), i.e., the product of beam radius at the beam waist with the far-field beam divergence angle.
How do you measure the quality of a beam?
M2 is measured on real beams by focusing the beam with a fixed position lens of known focal length, and then measuring the characteristics of the beam waist and divergence. These measurements can be taken with a laser beam profiler.
What is the M Squared?
The area equal to a square that is 1 meter on each side. Used for measuring areas of rooms, houses, blocks of land, etc. Example: A typical car parking space is about 12 square meters.
How do you calculate M2 of a beam?
