Beam propagation (m(2)) measurement made as easy as it gets: the four-cuts method

Area of Science:

• Optical Engineering
• Laser Physics

Background:

• Accurate measurement of laser beam quality is crucial for various applications.
• The M(2) factor quantifies beam propagation characteristics.
• Existing M(2) measurement methods can be complex or time-consuming.

Purpose of the Study:

• To develop an efficient and simplified M(2) measurement plan.
• To establish a straightforward method for determining the M(2) factor.
• To enable accurate laser beam quality assessment with minimal measurements.

Main Methods:

• Implementing a tolerance analysis for M(2) measurement.
• Performing initial beam diameter measurements within 0.5-2.0 Rayleigh ranges from the waist.
• Utilizing interpolation between second and third measurements on the opposite side of the waist.
• Conducting a final measurement halfway between matched diameters to determine the waist.
• Applying a two-parameter curve fit to the collected data.

Main Results:

• An efficient M(2) measurement plan was successfully developed.
• The proposed method simplifies the determination of the M(2) factor.
• Accurate M(2) values can be obtained through a minimal set of measurements and a simple curve fit.
• The plan demonstrates robustness through tolerance analysis.

Conclusions:

• The presented M(2) measurement plan offers an efficient and accurate approach.
• This method reduces measurement complexity and time.
• It provides a practical tool for laser beam quality assessment.