Introduction To Edge Filters

Edge optical filters are designed to selectively transmit or block wavelengths, categorized into short-pass and long-pass filters. Short-pass filters allow wavelengths below a specific cutoff, while long-pass filters permit wavelengths above it. A special case, dichroic beamsplitters, operates at an angle (typically 45°), reflecting unwanted wavelengths while transmitting desired ones, commonly used in fluorescence imaging.

Key specifications include edge location, transition width, and steepness, crucial in applications requiring high precision, such as Raman spectroscopy. Filters like EdgeBasic, RazorEdge, and Verona cater to different performance needs, with Verona offering the steepest transition widths for detecting low-wavenumber Raman signals.

Edge filters are widely used in fluorescence microscopy, next-generation gene sequencing, and clinical diagnostics, where they enhance signal-to-noise ratios. Microplate readers and PCR machines rely on long-pass filters to separate excitation and emission light for accurate biomolecular detection.

A unique advancement is VersaChrome tunable edge filters, which utilize angle-dependent wavelength shifts. These filters allow real-time spectral adjustments, aiding prototyping and adapting to laser wavelength variations due to thermal drift. By increasing the angle of incidence, the edge wavelength can shift up to 12%, making them valuable in dynamic laser applications.

Semrock offers a range of edge filters and dichroic beamsplitters optimized for fluorescence and Raman applications. Their precision designs, steep transitions, and high transmission rates make them essential in advanced optical systems, ensuring high-performance light control in various scientific and industrial applications.