Diode lasers operating around 915nm and 940nm are used in a variety of industrial, scientific, medical and technical applications. These near-infrared wavelengths are outside the range of normal visible vision, making appropriate eye protection particularly important.

When selecting laser safety glasses for a 915nm or 940nm source, the first step is to confirm the exact operating wavelength. The eyewear must have documented protection covering that wavelength rather than simply being described as suitable for infrared lasers.

Optical density (OD) is another important specification. The required OD depends on factors including laser power, operating mode and potential exposure conditions. A filter with an appropriate OD at 940nm, for example, should not automatically be assumed to provide the same level of protection at other infrared wavelengths.

Some laser safety filters provide broader wavelength coverage, which can be useful when equipment operates at multiple diode wavelengths. However, the complete specification should always be checked.

The physical design of the eyewear is also worth considering. Fit-over models can accommodate prescription glasses, while wraparound designs and side shields can provide additional coverage.

Laser safety glasses should be selected from the manufacturer's documented wavelength and OD ratings rather than lens colour or appearance. Correct selection ensures the filter is designed for the radiation produced by the specific laser system.