Laser-Line Longpass Filters

Our Laser Line Longpass filters offer unprecedented performance in longpass laser edge filter applications. The steep edges (measured from an optical density of 6.0 to a transmission of 50%) make it possible to measure even the smallest Raman shifts, making these filters a superior alternative to costly holographic notch filters for Stokes Raman scattering measurements. Compared to notch filters, these edge filters offer better transmission, higher laser-line blocking, and steeper edges, permitting measurement of Raman signals extremely close to the laser line. The large bandwidths and exceptional transmission permit these filters to be used in even the most demanding imaging applications.

Several unique features enhance the overall value of our laser Longpass filters. First benefit of our laser filters, the rejected laser source light is reflected, easing stray-light management issues associated with holographic notch filters. Eliminating the need for complicated light baffling simplifies system design, creating more compact, cost-effective instrumentation. Second enhancing feature of our laser filters, with guaranteed transition widths (measured from the laser wavelength to the 50% transmission wavelength) of <1%, angle-tuning is unnecessary, greatly simplifying system setup and implementation. And finally, the patent-pending coating process ensures unrivaled laser filter lifetime and durability, and guarantees “near-zero” temperature dependence, ensuring low long-term cost of ownership and maximum system operational range and sensitivity. These laser filters are not intended for general purpose longpass applications, as they do not have consistent blocking in the shortwave region.