Laser protective acrylic

Laser Protective Acrylic: An Insight into Its Functionality

Indeed, you only have one chance!

However, the reality is that the color orange is simply orange. Many companies that specialize in 'laser safety' are charging exorbitant prices for what is essentially standard colored acrylic. They toss around impressive statistics and 'Optical Density' (OD) figures, but in truth, they purchase commonly available acrylic and analyze it with a spectrum analyzer—a tool you could also acquire, though the cost of such a device outweighs that of basic acrylic sheets. I possess both transmissive and reflective spectrum analyzers, and my tests reveal that yellow to red acrylic sheets can absorb varying levels of 445nm light, ranging from over 50% to upwards of 90%.

Living in a remote area of Southeast Asia, obtaining 'laser safe acrylic' can be quite challenging, particularly when facing steep shipping fees of $150 for a small 12"x12" square.

In essence, 'laser safe' acrylic doesn't possess unique qualities; it's merely colored acrylic that effectively absorbs specific light frequencies. For instance, orange acrylic, which sits high on the visible spectrum (approximately 640-650nm), does not transmit lower spectrum colors but allows light within the orange range to pass through it.

Conversely, blue acrylic, found at a lower range (420-470nm), would transmit a 445nm laser while blocking a red diode laser at 640nm.

The specifics become critical, including a) the type of laser used—diode versus CO2, b) the power output of the laser, c) the spectrum being utilized—infrared or visible, and d) the acrylic's opacity.

For infrared lasers, even a clear acrylic sheet can block approximately 95% of IR light. However, a transparent sheet offers minimal protection against visible-light diodes. Notably, black acrylic is simple to cut—it absorbs energy and converts it effectively into heat.

So, there’s no need to panic. If you’re using a 500mW to 10W 'blue' laser diode, a sheet of 50% orange acrylic will sufficiently reduce the transmission of harmful rays to safe levels. Sure, dark sunglasses could provide similar protection, but using sunglasses alone without knowing the glass color and laser frequency is unwise for primary defense.

You can always test the acrylic’s effectiveness yourself—just place the sheet at a 90-degree angle to the laser beam, position a piece of tissue paper or similar flammable material, and fire. You’ll find that even focused beams won’t scorch the thin paper.

Reflection poses a significant risk of stray coherent light reaching unexpected areas. However, unless you’re cutting or engraving mirrors, the reflected beam tends to be considerably less powerful than the original beam. It will also experience some reduction in energy, prompting a shift to lower frequencies.

For those interested in DIY laser shielding, consider sourcing complementary colored acrylic together with 'one-way' reflective film to enhance safety. But remember to wear your protective eyewear at all times, even with added shielding. A single mishap can lead to severe consequences.

If you seek further information, please visit NB.

Click to expand...

Using Reflective Adhesive Film for Laser Safety