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Model NFC-446-040
Raman Notch Filter Assembly
Description:
The ARC Model NFC-446-040 is a filter chamber
designed to permit use of Raman notch filters with
ARC monochromators and spectrographs. It is
designed primarily to collect the output of fiber
optics, however it may be used with other sources
of Raman scatter (e.g., focused sample image or
direct collection of scatter from a sample
positioned close to the NFC-446040).
The standard NFC-446-040 includes a lens
chamber with sample holder designed to accept
1.5 inch diameter filters. Other sample holders are
available on a custom order basis. Filters can be
rotated up to 10° by an external micrometer in
order to tilt-tune the rejection band of the filter.
Principle of Operation: The NFC-446-040 is
designed to provide a collimated beam for
operation with notch (or cut-off) filters. The first
lens collects and collimates the beam through the
notch filter. The second lens collects the collimated
beam and focuses it to the entrance slit of the
monochromator or spectrograph. The light is then
dispersed to a detection system.
Notch filters are designed to significantly reduce (or block) the amount of laser light
reaching the monochromator or spectrograph, while transmitting the desired Raman
scatter. This permits efficient detection of the Raman scatter by the system without
requiring a double or triple monochromator. The integrated tilt adjustment capabilities
of the NFC-446-040 enable fine tuning of the notch filters to achieve the best
combination of laser light blocking and Raman scatter transmission.