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Table of Contents

Selecting and Using a Beam Dump

Overview

Beam dumps are used to safely absorb and terminate the laser beam at the end of its path or at intentional stopping points in a system. They are critical for protecting equipment, maintaining safety, and preventing back reflections that could interfere with upstream optics.

In a typical beam delivery system, beam dumps are placed at test ports, unused branches of beam splitters, or at the output of a system during alignment procedures.

Available Products

Looking for specs, dimensions, or part numbers? Explore our full range of beam dumps.

Specing a Beam Dump

Haas beam dumps are organized by aperture size: 19mm, 25mm, 38mm, and 50mm. Each part number reflects three key choices:

1. Aperture Size

  • Choose 19mm, 25mm, 38mm, or 50mm to match your beam path and system size.

  • We usually recommend a minimum of 1.5x times your beam diameter to avoid clipping or back reflections.

2. Absorber Coating

  • B = Brass coated cone – Best for IR (1064nm – 10.6µm)

  • C = Copper (uncoated) – Best for UV/Green (355nm – 532nm)

  • If your system is outside of this wavelength range please contact us for additional options.

3. Cooling

  • A = Air-cooled – For low to moderate power (less than 100 watts)

  • W = Water-cooled – For high power (less than 500 watts)

  • H = High-power water cooled – For multi-kilowatt lasers

  • Check the specs in the product page to learn more about the maximum power capabilities

Setting Up and Using a Beam Dump

Mounting and Alignment

  • Orient the dump face square to the beam.
    The beam should strike the absorber surface directly—off-axis hits can cause reflections or uneven heating.

  • Use a solid, stable mount.
    Beam dumps should be firmly mounted to prevent misalignment from vibration or accidental bumps.

  • Avoid line-of-sight backscatter.
    Even highly absorptive surfaces can reflect a small amount of light. Position the dump so any stray light doesn’t reach sensitive components.

Cooling and Power Handling

  • Air-cooled models are passive—make sure there’s adequate airflow and no heat buildup in enclosed spaces.

  • Water-cooled models require a coolant connection. Always double-check fittings and verify flow before powering the laser.

  • Let it stabilize.
    Beam dumps—especially high-power models—can experience slight thermal expansion. Let the system reach steady-state before final alignment.

Maintenance and Inspection

  • Check the absorber surface periodically.
    Look for signs of pitting, contamination, or discoloration.

  • Keep it clean.
    Use compressed air or a lint-free cloth to remove dust. Avoid touching the surface.

  • Replace when necessary.
    If damage is visible or performance drops, replace the dump to maintain safe operation.

Tips & Tricks

  • When in doubt, size up.
    If your beam diameter is close to the recommended limit, move to the next aperture size to avoid clipping and ensure easier alignment.

  • Use a beam dump during system alignment.
    Place one at the output to safely terminate the beam while mirrors and optics are being positioned.

  • Plan for backscatter.
    Even with high-efficiency absorbers, a small amount of light may reflect. If your system is sensitive, add shielding or use beam blocks in series.

  • Avoid long warm-up drifts.
    If using high-power lasers, allow the beam dump to reach thermal stability before final alignment. Mounts can subtly shift with heat.
  • Label your cooling lines.
    For water-cooled models, clearly label inlet and outlet lines. Misconnections can lead to flow issues or thermal overload.
  • Keep a spare.
    Especially in production environments, having a backup dump on hand can prevent unexpected downtime.