Gus Anibarro, Laser Institute of America
When working with visible lasers, it is very simple to find the beam path. Simply blow smoke in the path of the beam, and suddenly you can see the beam. However, working with invisible beams using lasers in the ultraviolet (UV) or infrared (IR) portions of the electromagnetic spectrum can become a bit of a challenge, but tools exist that can help you find the beam without much effort.
The first tool is the IR viewing card or disc. These cards or ceramic discs will glow when IR laser light strikes the card or disc, thus changing the IR radiation to visible radiation. When working in the UV spectrum, there are UV viewing cards and discs that operate similar to the IR cards and discs.
The second tool is the infrared viewer. IR viewers allow you to view the IR beam as it propagates through the air and is very useful in identifying stray beams from the controlled area. Some viewers can be connected to cameras or video monitors. Identifying stray beams in the UV can be done with the UV viewer.
The last tool for finding the laser beam is burn paper. Burn paper is sensitive to laser radiation and is used to visually display a laser beam's shape or mode structure. Burn paper is typically used for laser beam alignment. When the beam strikes the paper, an image of the beam is etched or burned onto the surface of the paper.
Remember when using all of the tools above, it is important that you always wear laser protective eyewear and practice laser safety.
Gus Anibarro is the education director for the Laser Institute of America (LIA). The LIA offers a complete line of laser safety training courses for personnel in research, industrial, and medical laser facilities. Onsite training is also available by contacting the LIA Education Department. All of LIA's courses are based on the ANSI Z136 Series of Laser Safety Standards.
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