Ondax’s SureBlock™ ultra narrow-band notch filters are the ideal solution for highly selective wavelength applications like low frequency (low wavenumber) 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, and 785nm. 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.

  • 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 Raman Spectroscopy
  • Structural Studies of Nanomaterials
  • Bio-medical and Solid State Laser Systems
  • Wide-band Notch Filter Replacement
Specification Summary
Table 1: SureBock™ Specifications
Parameter 488nm 514nm 532nm 633nm 78Xnm
Spectral Transition Width
(center to 50% transmission)
<10 cm-1 <10 cm-1 <10 cm-1 <10 cm-1 <10 cm-1
Optical Density at Laser Line (each filter) >4 >4 >4 >4 >4
Free Space Aperture Diameter Standard: 9mm in 1″ mount, Custom sizes available
Technical Data

Ultra narrow notch transition to 50% transmission

High Transmission on both sides of notch wavelength

Raman Spectroscopy