SureBlock™ ultra narrow-band notch filters

Ondax’s SureBlock™ ultra narrow-band notch filters are the ideal solution for highly selective wavelength applications like low frequency (low wavenumber) THz-Raman® spectroscopy.
With laser line attenuation of up to 99.9999% (optical density: OD4) and transition width of <10 cm-1, SureBlock™ filters can dramatically improve the ability of any Raman system to resolve low frequency Raman scattering. High transmittance on both sides of the notch enables both Stokes and anti-Stokes Raman spectra to be observed simultaneously.
Individual filters are mounted in 1” housings for compatibility with standard 1” optical systems. Alternatively, our SureBlock™ XLF Series THz-Raman® Spectroscopy and Filter Systems integrate the notch filters into a rugged, pre-aligned, light-tight enclosures with optional laser sources, ASE filtering, and free space or fiber inputs & outputs.

Available at standard Raman wavelengths: 488, 514, 532, 633, 785, 808, 830, 976 and 1064nm. Custom wavelengths are available on demand. We also recommend the use of our NoiseBlock™ ASE Filters and 90/10 Beamsplitter Filters to achieve optimum performance of the notch filters when using diode or diode-pumped laser sources Ondax SureBlock™ Notch filters are reflective volume holographic filters (VHGs), produced in a proprietary glass designed for long lifetime, high efficiency and excellent transmission. Ondax’s fabrication process is highly stabilized to ensure excellent part-to-part repeatability.

SureBlock™ Ultra-Narrowband Notch Filters


  • Ultra narrow rejection bandwidth
  • Highly repeatable performance
  • Environmentally stable at high temperature and humidity
  • No degradation over time, even under high power illumination conditions


  • Low Frequency THz-Raman® Spectroscopy
  • Structural Studies of Nanomaterials
  • Bio-medical and Solid State Laser Systems
  • Wide-band Notch Filter Replacement
SureBock™ Specifications
Parameter 488nm – 1064nm
Spectral Transition Width (center to 50% transmission) <10 cm-1
Optical Density at Laser Line (each filter) >4
Free Space Aperture Diameter Standard: 9mm in 1″ mount, Custom sizes available

Ultra narrow notch transition to 50% transmission

Ultra narrow notch transition to 50% transmission

High Transmission on both sides of notch wavelength

High Transmission on both sides of notch wavelength

SureBlock™ - Ultra Narrow-band Notch Filters

SureBlock™ – Ultra Narrow-band Notch Filters