Infrared Optics Handling and Cleaning

Optics can be easily damaged or contaminated from poor handling and incorrect cleaning methods.  Be sure to consider the following guidelines:

  • To minimize the amounts of defects caused by surfaces coming into contact with other surfaces never place optics on hard or rough surfaces.  Optics can be easily scratched and chipped.
  • When handling and cleaning an optic only perform work on clean, tissue covered surfaces.
  • Optics should never be handled without finger cots or Latex/Nitrile gloves to avoid transferring oils and dirt from the skin which can be difficult to remove and damage coated and uncoated surfaces.
  • Use tweezers or other tools to clean very small parts only when absolutely necessary.
  • Use Cotton Pads or lens tissue only when cleaning surface of a coated lens or protected mirror.
  • Never contact clean uncoated mirror or unprotected mirror surface.  Only dry nitrogen or filtered air should be used to remove particulate form these surfaces.
  • Apply solvent directly to your cloth.  With wet pad with material specific approved solvent Use slow, even, light pressure working from edge to edge across the optic allowing solvent to evaporate directly behind pad.
  • Cover the optic and store in dry – dust free area immediately after cleaning.
  • When selecting a solvent for cleaning un-mounted optical components both substrate material and coating composition should be taken into consideration.
  • Cleaning mounted optics in assemblies should take into consideration the compounds or epoxies used to secure lens.  These are often not resistant to solvents and could damage or cause chemical reaction if improperly cleaned.
  • Choice of solvent should also be consistent with the FOD (Foreign Object Debris) that is being be removed.  Particulate dust should be removed with air or nitrogen when possible.

Janos Technology takes pride in shipping clean, ready to use optical components and assemblies.  If you receive contaminated optical surfaces please contact your sales associate for instructions or a Return for Maintenance Authorization (RMA).  If you have a Janos Technology optical component or system that has been soiled or contaminated in the field and would like it serviced by our trained staff please contact your sales associate.


  1. Acetone (Spectranalyzed) Specific for UV and Infrared ranges.
  2. Ethyl Alcohol (Denatured)
  3. Isopropanol (99.9%)
  4. White Vinegar (Distilled) 5% acidit
  • Only used in mixture 80% Acetone 20% Vinegar, followed by 100% Acetone pad to be used to remove and Vinegar residue.

NOTE 1: Some coatings will break down when contacted by any Acidic solution.  This should only be used if the chemical composition of the substrate and the coating is resistant to Acidic solutions.  This method is commonly used to remove oils from fingerprints or saliva from optical surfaces. 

Recommended for Uncoated and Coated Materials

Uncoated Materials Solvent(s)
Aluminum (Al) 1
Barium Fluoride (BaF2) 1, 2
Calcium Fluoride (CaF2) 1, 2
Germanium (Ge) 1, 2, 3
Infrared Glass (Black Diamond, GASIR, IG Series) 1
Sapphire 1, 2, 3
Silicon (Si) 1, 2, 3
Zinc Selenide (ZnSe) 1, 2, 3
Zinc Sulfide (ZnS) 1, 2, 3
Coated Materials
Anti-Reflective Coating (AR) 1, 2, 3, 4   *See Note 1
Diamond Like Carbon Coating (DLC) 1, 2, 3, 4   *See Note 1
Dielectric Coating 1, 2, 3
Hard / Protected Metallic 1, 2, 3
Unprotectd Metallic / Uncoated Metallic Air, Nitrogen