B71408 Dual-Band Filter

The B71408 passes the blue-to-green spectrum with its 50 % cut-off measured at 531 nm. Transmission averages above 90 % from 410 to 520 nm, peaking at 93.5 % near 470 nm, providing broad coverage from the deep blue to the blue-green boundary. Beyond the cut-off, the filter suppresses transmission to below 1 % by 547 nm and maintains sub-0.5 % blocking on average from 547 nm to 780 nm – a clean, wide rejection floor with minimal NIR leakage.

Key Advantages

• Precise 531 nm cut-off – T50 % measured at 530.8 nm with a transition that drops to < 1 % within 16 nm, cleanly separating the blue-green passband from the yellow-green region.
• High-throughput passband – Average transmission above 90 % across 410–520 nm with a 93.5 % peak, minimizing signal loss across the wide blue-to-green range.
• Broadband blocking – Sub-0.5 % average transmission from 547 nm to 780 nm, providing reliable rejection of yellow, red, and NIR wavelengths.
• Hard-oxide durability – Ion-assisted sputtered hard coating withstands heat, humidity, solvents, and frequent cleaning cycles.
• Custom formats – Round, square, or free-form blanks from 5 mm to 450 mm, thickness 0.21–3.8 mm, on Borofloat, soda-lime, Schott D263 T, or Corning Eagle XG substrates.

Typical Applications

• Fluorescence excitation filtering – Passes the full excitation band for GFP, FITC, and Alexa Fluor 488 while blocking emission wavelengths above 530 nm.
• Multi-channel microscopy – Defines a wide blue-to-cyan channel in multi-color fluorescence imaging, preventing cross-talk with yellow or red detection channels.
• Laser line clean-up – Removes broadband background from 488–514 nm laser sources, passing only spectrally pure blue-green illumination.
• Machine vision – Isolates blue-green LED illumination in automated inspection systems requiring rejection of yellow and red ambient light.
• Architectural & stage lighting – Produces a pure cyan-blue wash from broadband sources with zero yellow or warm-tone spill.

Need a 540 nm shortpass tailored to your optical path? KUPO Optics provides rapid prototyping and volume production to your exact size, shape, and substrate specifications.