BH-N20 Broadband Notch Filter
Double-pass notch filter passing vivid violet (400 – 480 nm) and rich red (610 – 750 nm) while plunging green-cyan light below 1 % for a clean magenta spectrum.
- Violet passband: > 90 % T @ 400 – 480 nm
- Deep notch: < 1 % T @ 500 – 577 nm
- Red passband: 610 – 750 nm, 92 – 95 % T
- Red plateau: Ripple ≤ ±2 % keeps colour flat
- Construction: Ion-assisted hard-oxide; 5 – 450 mm shapes, 0.21 – 3.8 mm thick
- Custom options: Ripple smoothing, AOI tuning, rapid prototypes
Learn more
BH-N20 opens two clear optical windows—one in the violet-blue band
(≈ 400 – 480 nm) and one in the visible- to deep-red range (≈ 610 – 750 nm)—while
driving the green-cyan region down to detector noise. Transmission peaks around
90 – 93 % across each passband, drops below one percent from ~500 nm to 577 nm, then
rebounds above 90 % near 610 nm and rides a smooth 92 – 95 % plateau beyond
750 nm before tapering gently into the near-IR.
KUPO coats Borofloat®, soda-lime, Schott D263 T, or Corning Eagle XG substrates in any
outline—from 5 mm chips to 450 mm plates—with thicknesses of 0.21 – 3.8 mm,
and can ship prototypes in about two weeks.
Typical uses: violet-excite/red-detect fluorescence, magenta stage lighting,
UV + red machine-vision illumination, green-band suppression in Raman or multispectral
sensors, and AR/HUD optics that need violet tracking plus red graphics without
mid-visible clutter.
Description
BH-N20 opens two clear optical windows—one in the violet‐blue range and one in the deep red—while forcing almost every photon in the green–cyan band down to detector noise. Transmission climbs past 90 % by ~400 nm, remains flat through roughly 480 nm, then plunges below 1 % from about 500 nm to 577 nm. It rebounds above 90 % again near 610 nm and holds a smooth 92 – 95 % plateau out past 750 nm. The result is a vivid magenta spectrum that keeps violet excitation and red detection bright but strips away mid-visible clutter.
Key advantages
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Deep 500 – 577 nm notch – < 1 % T scrubs green autofluorescence and ambient spill.
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High dual passbands – > 90 % T in 400 – 480 nm and 610 – 750 nm maximises violet sources and red detectors.
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Flat red plateau – Ripple held to ±2 % delivers uniform colour and stable signal.
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Hard-oxide durability – Ion-assisted coating resists heat, humidity, solvents, and repeated cleaning.
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Custom formats – Round, square, or free-form blanks from 5 mm to 450 mm, 0.21 – 3.8 mm thick, on Borofloat®, soda-lime, Schott D263 T, or Corning Eagle XG glass.
Typical applications
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Fluorescence microscopy & cytometry – Pass violet excitation and red emission while silencing green background for sharper images.
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Raman & multispectral sensors – Block 532 / 561 nm laser lines yet keep violet and red Stokes or anti-Stokes bands.
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Stage & architectural lighting – Produce saturated magenta washes (violet + red) with negligible green spill.
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Machine-vision systems – Combine UV flaw detection with red contour lighting, eliminating mid-band reflections.
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AR / HUD optics – Inject violet tracking beams and red graphics while keeping the central visible band dark to the eye.
Need prototypes in days or production volumes next quarter? BH-N20 filters can be coated, diced, and shipped to your exact specifications—fast.
