Notch Filters

Notch filters are used to block a narrow range of wavelengths. In Raman spectroscopy, this allows observation of Stokes (long wavelengths) and Anti-Stokes (short wavelengths) scattered light while blocking the laser line. High transmittance in the passband and deep blocking at the excitation laser line (OD > 6) provides more signal with less background. We offer notch filters with a CWL from 442nm to 1550nm and beyond.

Iridian specializes in providing custom notch filter solutions for a wide range of applications. Our in house design software, multiple process options and 20 years’ experience dealing with a wide range of applications allow you to optimize notch filter performance and cost for your needs. Our filters are all deposited using energetic sputtering, ensuring a hard durable, environmentally stable coating. The resulting filters also have exceptionally high transmittance levels and blocking from the visible to the MWIR (300nm to 10um). We partner with you from prototype to volume production to support you and the success of your business.

Iridian’s edge filters offer:


  • High transmission in the bandpass region- typically greater than 93%
  • Accurate wavelength control and uniformity
  • Low passband ripple
  • Steep slopes from full transmission to full blocking
  • Blocking >OD6 at laser line
  • CWL at any wavelength from the UV to the mid IR (~340nm to 10 µm)


Applications for our notch filters include:

Raman Spectroscopy

  • Your application – OEM and custom


We also offer a wide range of standard filters available for immediate purchase online.

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Contact us for your notch filter requirements.

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Tel:  +1 (613) 741-4513
Fax: +1 (613) 741-9986