In Raman spectroscopy applications, emitted light is very close in wavelength range to the excitation light. In order to attenuate a laser’s signal from reaching the detector while at the same time transmitting the weak emitted light signal, notch or edge pass Raman filters are required. Because of their high transmittance and extended deep blocking, Raman laser line filters are also required to ensure that only the desired wavelength is actually illuminating the sample being tested. This page provides an overview of Iridian Spectral Technologies' line of filters for Raman spectroscopy.
Raman Laser Line Filters
Iridian Spectral Technologies' line of Raman laser line filters feature greater than 90% transmittance in the pass band, a 1-3 nm bandwidth, and excellent blocking in the 300 nm to 1200 nm wavelength range. They reduce a laser’s spectral noise and pass a desired laser wavelength through a steep transition from pass band to deep blocking.
Raman Notch Filters
Notch filters allow the observation of long (Stokes) and short (anti-Stokes) wavelength light while blocking the laser line in Raman spectroscopy applications. A combination of high transmittance (>90%) and deep blocking (OD>6) results in more signal with less background. Iridian Spectral Technologies offers both narrow and standard notch filters.
Raman Edge Filters
In Raman spectroscopy edge pass filters allow either Stokes (long wavelength) or anti-Stokes (short wavelength) scattered light to reach the detector while removing the excitation laser source. Iridian Spectral Technologies offers both short and long pass Raman filters with industry leading cut-off values (as low as 25cm-1 from OD6 at the laser to the 50% point) to enable detection Raman signal extremely close to the laser line.
In addition to the filter types listed above, Iridian Spectral Technologies also offers dichroic short pass and long pass filters. Contact them to learn more.