Semrock designs and manufactures the highest performance edge filters available for Raman spectroscopy.

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In Raman spectroscopy applications, intense laser beams are used to create Raman scattered light from a sample under test. The Raman "finger print" is measured by a spectrometer. Optical filters are critical components in Raman spectroscopy systems to prevent all undesired light from reaching the spectrometer.

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Laser transmitting filters inserted between the laser and the sample block all undesired light from the laser. Laser blocking filters inserted between the sample and the spectrometer block the Rayleigh scattered light at the las

er wavelength.

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There are four basic types of filters to choose from: long-wave-pass edge filters, short-wave-pass edge filters, notch filters and laser-line filters. Laser-line filters are an obvious choice as laser transmitting filters, and notch filters and edge filters can both be used as laser blocking filters.

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The standard Raman spectroscopy layout

Which one to choose depends on the application, for example if both Stokes and Anti-Stokes Raman scattering should be measured simultaneously, or if the steepest possible edge for looking at the smallest Stokes shifts is desired.

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However, in many high-performance Raman systems – such as those with microscopic imaging capabilities or highly sensitive remote probes –complex focusing and collection optics are used to couple the system to the sample region. For these systems it is desirable for the excitation laser beam and the Raman-shifted signal light to share a common light path, and this is done by a dichroic beamsplitter.

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​For more detailed information about Semrock and Raman filters, please see links under Partners or under Dialogue/Downloads.

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Please contact us to discuss Raman filters.