Optic cleaning is not a required component of a regular laser system maintenance schedule. Optics should only be cleaned as a corrective action for marked power decrease or poor mode quality. Optics should not be cleaned unless signs of contamination are clearly visible on the optic surfaces. Unnecessary cleaning will shorten the life span of the optical coating.
Optics and optic coatings can be easily damaged. Never touch the optical surfaces with bare skin, hemostats, or materials other than lens tissue.
The Hemostat and Lens Tissue Method
- If applicable, place the laser system in Current control mode of operation. For Ion laser systems disengage PowerTrack if this option is available. Record the laser system output power, and output mode characteristics if applicable. Turn off the laser system, or block the pump laser beam if the optic to be cleaned is in an oscillator or amplifier.
- Inspect the system optics for contamination. Clean an optic only if contamination is clearly visible. A bright flashlight, held a glancing angle of incidence with respect to the optical surface, can help to identify contaminated optics.
- Fold a lens tissue into a 1-cm (3/8-in.) wide strip, being careful not to touch the portion of the tissue that will contact the optic.
- Fold this strip upon itself twice and grasp near the fold with clean hemostats as shown in the figure below.
- Place a few drops of Methanol on the fold and shake off the excess.
- Make a single swipe across the surface of the optic. Do not re-use the lens tissue as particles of dust and other contaminates picked up from the surface of the optic may scratch if dragged across with a second swipe.
- Turn on the laser system, or unblock the pump laser beam. Using only the mount tilt controls of the optic that was cleaned, optimize the performance of the laser system. Do not clean another optic until the system performance meets or exceeds that previously recorded.