M4904 Broadband Notch Filter
Double-pass notch filter passing vivid violet (390 – 445 nm) and red/NIR (625 – 760 nm) while driving green-cyan light below 1 %—perfect for magenta optics.
- Violet passband: 390 – 445 nm, > 90 % T
- Deep notch: < 1 % T 470 – 595 nm
(valley ≈ 0.2 % T) - Red/NIR passband: 625 – 760 nm, 92 – 95 % T
- Edge steepness: ~15 nm 90 → 10 % transitions
- 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
M4904 transmits two bright windows—one in the near-UV/violet (≈ 390 – 445 nm) and one in the red/near-IR
(≈ 625 – 760 nm)—while driving the entire green-cyan band to detector-noise levels. Transmission stays above
88 – 92 % from ~395 nm to 445 nm, drops below one percent from ~470 nm to 595 nm, then rockets past 90 %
again by ~625 nm and rides 92 – 95 % out beyond 750 nm. Ion-assisted hard-oxide coatings shrug off heat,
humidity, solvents, and repeated cleaning. KUPO can coat Borofloat®, soda-lime, Schott D263 T, or Corning
Eagle XG glass in any outline—from 5 mm chips to 450 mm plates, 0.21 – 3.8 mm thick—and ship prototypes in
about two weeks.
Typical uses: violet-excite/red-detect fluorescence, magenta stage lighting, UV + red
machine-vision, laser-line suppression in Raman sensors, and AR/HUD optics needing violet tracking plus red
graphics with the mid-visible kept dark.
Description
M4904 transmits two bright windows—one in the near-UV/violet (≈ 390 – 445 nm) and one in the red/near-IR (≈ 625 – 760 nm)—while driving the whole green-cyan band to detector-noise levels. Measured transmission stays above 88 – 92 % from ~395 nm to 445 nm, collapses to below 1 % from roughly 470 nm to 595 nm, then rockets past 90 % again by ~625 nm and holds 92 – 95 % out beyond 750 nm. The spectrum is ideal whenever you want vivid magenta light—or need to combine violet excitation with red detection—without mid-visible contamination.
Key advantages
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Deep mid-band notch – < 1 % T across ~470 – 595 nm suppresses green autofluorescence and background glare.
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High dual passbands – > 90 % T in 390 – 445 nm and 625 – 760 nm keeps violet excitation and red emission bright.
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Broad blocking floor – Mid-band floor down to ~0.2 % boosts signal-to-noise in demanding imaging tasks.
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Hard-oxide durability – Ion-assisted coating withstands heat, humidity, solvents, and repeated cleaning.
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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 glass.
Typical applications
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Fluorescence imaging & flow cytometry – Pass violet excitation and red emission while silencing green background for cleaner contrast.
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Raman & multispectral sensors – Block a 532 nm or 561 nm laser line yet keep violet and red Stokes/anti-Stokes bands.
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Stage & architectural lighting – Create saturated magenta washes (violet + red) without green spill.
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Machine-vision systems – Combine UV crack 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? M4904 filters can be coated, diced, and shipped to your exact specifications—fast.
