Beam Expander Selection Guide

In many laser based applications, beam expanders are an essential component of the optical system. They are most often used to decrease divergence or to create smaller final focused spot sizes by expanding the beam before the final focusing element. They are also used to increase beam diameter, therefore reducing power density or facilitating alignment.

Once you have determined the need for a beam expander, selecting the correct beam expander can be a daunting task due to the numerous options available. The table below displays a selection guide for determining which Edmund Optics^® (EO) beam expander will best fit your application.

Tables 1 and 2: Selecting the right beam expander for your application requires knowledge of many different parameters. Edmund Optics offers a variety of beam expanders with different specifications, sizes, and prices to best fit your application requirements.

The first step is determining whether fixed or variable magnification is required. For variable magnification applications, EO offers the Research-Grade Variable Beam Expanders (RVBX).

For fixed magnification applications, the laser wavelength, input aperture, and required transmitted wavefront performance must first be determined. For cost sensitive applications at Nd:YAG wavelengths, EO offers Scorpii Nd:YAG Beam Expanders. These beam expanders have an entirely fixed optical design and offer diffraction limited performance for Nd:YAG fundamental wavelengths, first harmonics, and second harmonics.

For applications where divergence adjustment is required to collimate converging or diverging input beams, or alternatively to create a controlled, slightly convergent or divergent output, Vega and Draconis Fixed Beam Expanders are the best choice. For Nd:YAG wavelengths, the ideal options are the Vega Laser Line Beam Expanders and Draconis Laser Line Beam Expanders. The Vega Laser Line Beam Expanders offer excellent value, with λ/10 performance, coatings for Nd:YAG wavelengths up to the fourth harmonic, and input apertures up to 10mm. Compared to the Vega Laser Line Beam Expanders, the Draconis Laser Line Beam Expanders are the premium option due to their non-rotating optics and larger apertures.

The Arcturus HeNe Beam Expanders are designed specifically for use with HeNe lasers, and feature non-rotating optics in divergence adjustment. Both Vega and Draconis broadband versions are designed for broadband use, offering a selection of broadband coatings covering 260 – 2100nm, and λ/10 performance at their design wavelength, with the key difference between the two families being rotating vs non-rotating divergence adjustment mechanism.

The decision tree below provides a visual method of determining which Edmund Optics beam expander meets your application requirements.

When standard or stock options do not meet your criteria, custom versions can be designed. Some custom requirements allow for quick modifications on standard beam expander designs, allowing for a rapid, cost-effective turnaround.

Contact us to discuss your specific requirements with one of our Application Support Engineers.