Collection: Neutral Density FIlter

The primary purpose of an ND filter in this context is to reduce the intensity of the laser beam without altering its other properties. This is essential because most beam profilers and other measuring devices have a damage threshold, which specifies the maximum intensity their sensors can withstand before damage occurs. By attenuating the laser beam before it reaches the measuring device, ND filters help ensure the accuracy, reliability, and longevity of the equipment.

How they are used in laser applications:

• They are typically employed as a last line of defense before the beam reaches the measurement sensor. For high-powered lasers, other accessories like beam splitters and expander/reducers are used first.
• Multiple ND filters can be placed in series to achieve different levels of total attenuation.
• When stacking filters, it is recommended to position the weakest (less attenuating) filters first and the strongest closest to the measuring sensor.
• It is important that the laser beam strikes the filter at a 90-degree angle (perpendicular) when used in series. Failing to do so can result in reflectivity, optical resonance, adversely impact transmission quality, and potentially damage the filters.

It is noted that ND filters are not designed to be high-powered attenuators. Applying excessive optical power to them can lead to thermal beam distortions, thermal lensing, and other types of laser-induced damage to the filter itself.

ND filters are considered a must-have for most laser calibration, testing, and measuring applications. Attenuation is a key priority regardless of the laser system or measuring equipment to ensure accurate readings and, most importantly, to avoid exceeding the equipment's damage threshold.