The laser supplied with each standard SPPDI® is based on a modified commercial Class 3R (IEC 60825-1) or Class IIIa (old system) collimated laser diode module (LDM), operating at a wavelength of 650 nm, with a CW (continuous wave) optical output power of about 5 mW (milliwatts). After the collimating lens is removed, the lens-less LDM is installed in the SPPDI Laser Adapter, and the Laser Adapter is attached to the SPPDI enclosure. The diverging laser beam emitted by the SPPDI at the Main Port is collimated by a 9 mm diameter f/7.9 lens. A 7 mm diameter portion of the collimated 9 mm diameter beam is measured with a calibrated laser power meter to ensure that the output laser beam power is less than 0.35 mW. This low level of emitted beam power places the SPPDI in the category of a Class 1 (non-hazardous) laser device, with very low probability of ocular damage even after long-term exposure to the beam.
Warning: Removal of the Laser Adapter from the SPPDI will void the product warranty, and will void the FDA/CDRH registration of the SPPDI as a Class 1 (IEC 60825‑1) or Class I (old system) laser product (CDRH Accession Number 1811033-000). The laser point source provided with the SPPDI is comprised of a commercial collimated Class IIIa laser diode module (LDM) with the collimating lens removed. The NOHD (Nominal Ocular Hazard Distance) for the diverging beam produced by the lens-less LDM is about 6 inches. Viewing the diverging laser beam emitted by the lens-less LDM outside the SPPDI at a range closer than 6 inches without proper eye protection may result in ocular injury.
Caution: if the user chooses to remove the Laser Adapter and/or replace the laser module supplied with the SPPDI with their own laser source, the Laser Class designation and associated warning label supplied with the SPPDI will no longer apply. Furthermore, the SPPDI warranty will be voided.
Attention: Please review the SPPDI® Warranty policy before purchasing any of the SPPDI products. A link to this policy is also available at the Store.
Although caution when viewing light derived from a laser source is always advised, direct viewing of the laser light exiting the SPPDI instrument ports through the supplied Viewing Telescope is one of the preferred operational modes for the SPPDI. This is safe because the optical output power emitted from the instrument ports of an unmodified CDRH‑registered SPPDI, when properly adjusted for viewing high contrast interference fringes, is typically in the sub-microwatt (nanowatt) range. When viewed with the viewing telescope supplied with the SPPDI, the test article appears as an extended source covering a large portion of the retina, at a comfortable and safe level of optical power.
As a further precaution, if the user is still concerned about observing the laser light exiting the SPPDI through the supplied Viewing Telescope, a digital camera with a sufficiently large sensor (e.g., APS-C size sensor) and a mild “fast” (f/2.8 or “faster”) telephoto lens (e.g., 85 mm focal length) may be placed near the supplied eyepiece of the Viewing Telescope to intercept and display the light exiting the SPPDI instrument port.
Alternatively, for high precision interferometry, the supplied Viewing Telescope can be easily removed from the SPPDI instrument port. The test article may then be viewed by placing the digital camera in the diverging output beam emitted from the open SPPDI Instrument Port, with the camera lens focused on the test article. A longer focal length (e.g., 85 mm) “fast” (e.g., f/1.8) mild telephoto lens has been found to work well with this type of setup.
