Optical filters

Technical Notes

Custom sizing
Spectrogon’s filters and windows are produced in sizes from Ø6.0 to Ø200.0 mm. Custom sizing service is available at a modest surcharge. The wafers can be diced to custom-made sizes, down to as small as 1.0×1.0 mm. To minimize handling and cost, Spectrogon can offer – on most filters and windows – cutting and delivering on tape . Also turning down to smaller diameter is possible.

Spectral measurements
All filters are shipped with an individual spectral scan or, in the case of multiple similar filters in the shipment, one scan per lot. The spectral scans are taken at room temperature and at normal angle of incidence showing the relevant wavelength region of the filter.

Nonstandard spectral measurements
Please see Prices Thin Film Services

Environmental tests
Please see Prices Thin Film Services. Other tests can be performed upon request.

Cleaning and handling of filters
Spectrogon’s filters are designed and manufactured to withstand the most stringent environmental conditions. However, all optical components deserve special consideration in handling, caring and storage. All Spectrogon filters are inspected prior to shipment and packaged in special protective containers. No extra cleaning should be necessary upon receipt.

All unnecessary handling of filters should be avoided to reduce the possibility of damage. The filters should be handled by the edges. Try to avoid handling the filter surfaces. Preferably, all work with the filters should be done in a clean environment, eg. laminar flow cabinet or similar. Ideally, normal clean room procedures should be applied.

If a filter surface is dirty or stained, it can possibly be cleaned. In most normal cases filters may be cleaned with a solution of lukewarm water and mild detergent, providing the substrate and/or the coating is not water soluble, according to the following procedure:

• Wet a lens cleaning tissue with water/mild detergent solution and wipe the filter surface gently until the surface is clean.
• Rinse off with distilled water and immediately wipe dry with a lens cleaning tissue.

If the filter is left to dry in air permanent drying stains may appear.

Impurities that are not cleaned with the water/mild detergent method or if the substrate/coating is soluble in water, isopropyl alcohol or acetone cleaning can be used.

Wet a lens cleaning tissue with the solvent and trail wipe the surface several times until the surface is clean.
Thereafter, immediately wipe dry with a dry lens cleaning tissue.

If in doubt, contact one of our Spectrogon sales engineers by e-mail on sales.se@spectrogon.com