More and more fields of application are being conquered by multi- and hyperspectral imaging. As a result, new demands are constantly being placed on optical filters in particular. Due to the high demand for complex high-performance filters, Materion Precision Optics has decisively developed linear variable filters. A special coating technology now allows the production of linear variable graduated filters with extraordinary spectral performance.
The graduated filters are offered as short-pass, long-pass, and band-pass versions, whereby the respective spectral ranges can be adapted customer-specifically from 300nm to the NIR. During filter development, special attention was paid to the steepness of the spectral edge. This now allows the realization of FWHM of less than 2% of the reference wavelength, making them particularly suitable for hyperspectral cameras. At the same time, high transmissions in the passband are guaranteed. Peak transmissions of >97% allow the measurement of even the smallest signals. The filter blocking is optimized for the spectral range of Si-based sensors and reaches average values of OD5, guaranteeing an optimal signal-to-noise ratio. Customized filter designs even achieve OD8 blocking. Therefore, these filters are also especially suitable for use in fluorescence microscopy applications.
The gradient, as well as the filter size, of the newly developed variable filters are customizable, making them suitable for pushbroom and snapshot sensors of various dimensions. With outstanding environmental stability, the RoHS-compliant filters can also be used in demanding environmental conditions.
