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VIS Bandpass Filter

Photonics Spectra
May 2012Delta Light & Optics’ family of linear variable filters is extended with a sixth type — the LVVISBP visible model.

A linear variable bandpass filter is a wedged filter whose spectral properties vary linearly along the long side of the filter. The position of the center wavelength can be adjusted by sliding the filter with respect to the incident light.

A single linear variable filter can replace a number of dedicated filters in an instrument, decreasing complexity and cost. This opens up new design possibilities for analytical and diagnostic instruments such as spectrometers.

By combining linear variable short- and long-pass filters, bandpass filters can be constructed to be tuned continuously with center wavelengths from 320 to 850 nm, with the added benefit of tunable bandwidth.

Besides setting new standards in transmission level and edge steepness, the filters offer blocking levels better than OD 3 over the complete reflection range, or even OD 5 when two filters are placed in series.

The filters are coated on single quartz substrates for minimal autofluorescence and a high laser damage threshold. All are coated with ultrahard surface coatings that offer higher packing density than traditional hard coatings.

The coatings provide good spectral stability with no drift, increased lifetime, optimal mechanical stability and minimal water uptake. More products