What is a Beam Expander?

Laser beam expanders increase the diameter of a collimated input beam to a larger collimated output beam for applications such as laser scanning, interferometry, and remote sensing. Contemporary laser beam expanders are a focal system developed from well-established optical telescope fundamentals. In such systems, the object rays enter parallel to the optical axis of the internal optics and exit parallel to them. This means that the entire system does not have a focal length.

The laser beam expanders will increase the diameter of the collimated laser to a larger collimated output laser.  Laser beam expanders are similar to telescopes. Both utilising two lenses. The 1st lens has a larger diameter than the laser source. The 2nd lens should also be larger than the desired output size of the laser.

Galilean Type:

A combination of a convex and concave lens

  • Shortens the overall length of the beam expander
  • High performance with a small number of lenses
  • Usable with high powered lasers

Keplerian Type:

Utilises two convex lenses

  • Able to insert a pinhole into the expander
  • Able to obtain a clean Gaussian beam emitted by the effect of the pinhole spatial filter

Note: Not allowed to be used for high energy lasers. It can cause sparks at the focal point of the laser causing the transmitted wavefront to collapse.

High Power Laser Beam Expander

These laser beam expanders are designed for the use of high powered lasers. Allowing for fine adjustment of the collimator, this is done so with the available diopter correction function. The optical system of the beam expander utilises an air gap configuration that does not use an adhesive bonding of the lens.

The lens is design takes into account the wavefront aberration. so it can be used in an optical system with high precision, such as laser interferometer or laser processing.

High-Power Zoom Laser Beam Expander:

It is capable of 1x to 3x times changing high-power zoom laser beam expander. It can be used in an optical system with high precision, such as a laser interferometer and processing by the lens design that takes into account the wave front aberration.

The optical design of the beam expander is an air gap configuration that does not use an adhesive to bond the lenses. This allows the beam expander to be used with a high-power laser. 

By turning the diopter ring that is attached to the centre of the beam expander, you can make variable beams such as the focused beam, collimated beam and divergent beam. It is used when you want to vary the position of the beam. 

By turning the diopter ring that is attached to the centre of the beam expander, you can make variable beams such as the focused beam, collimated beam and divergent beam. It is used when you want to vary the position of the beam.