R2918 Longpass Filter
Long-pass filter blocking green-cyan (< 585 nm) while passing 92–94 % rich red light (615 – 780 nm) for warm, glare-free output.
- Red passband: 615 – 780 nm, 92 – 94 % T (± 2 % ripple)
- Cut-on (T50): ≈ 600 nm
- Edge steepness: ~15 nm (10 → 90 % transition)
- Blue-green blocking: < 1 % T below 585 nm
- Construction: Ion-assisted hard-oxide; 5 – 450 mm shapes, 0.21 – 3.8 mm thick
- Custom options: Edge tuning, ripple smoothing, 45° AOI, rapid prototypes
Learn more
R2918 holds transmission below one percent up to roughly 585 nm, reaches
the 50 % mark near 600 nm, and clears 90 % by ~615 nm. It then rides a
smooth 92 – 94 % plateau past 780 nm with ripple limited to ±2 %. The
ion-assisted hard-oxide stack withstands heat, humidity, solvents, and
repeated cleaning. KUPO coats Borofloat®, soda-lime, Schott D263 T, or
Corning Eagle XG substrates in any outline—from 5 mm chips to 450 mm
plates, 0.21 – 3.8 mm thick—and can ship prototypes in about two weeks.
Typical uses: LED colour tuning, far-red fluorescence capture,
cyan-glare suppression in machine vision, daylight-to-tungsten warming for
film lighting, and AR/HUD red-graphic injection without blue-green bleed.
Description
R2918 keeps transmission below 1 % up to roughly 585 nm, crosses the 50 % point near 600 nm, and clears 90 % by about 615 nm. From there it rides a flat 92–94 % plateau to at least 780 nm, with ripple contained to ±2 %. The profile is tuned for lighting or imaging tasks that need a clean, high-power red band—without relying on gels or stacking extra optics.
Key advantages
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Sharp green–cyan cutoff – 50 % cut-on ≈ 600 nm; < 1 % T maintained to ~585 nm for minimal shorter-wavelength leak.
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High, flat red passband – 92–94 % T from ~615 nm to 780 nm keeps brightness and colour balance stable.
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Hard-oxide durability – Ion-assisted coating stands up to heat, humidity, solvents, and repeated cleaning.
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Flexible formats – Round, square, or custom 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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LED colour tuning – Remove cool spikes in white or RGB fixtures to create warm, red-rich ambience.
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Fluorescence emission – Collect far-red probes (Cy5, Alexa 647, mPlum) while blocking green–cyan excitation.
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Machine vision – Strip cyan reflections from reflective parts while keeping the red channel bright for defect detection.
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Photography & cinema lighting – Warm daylight LED panels toward a tungsten look without gels.
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AR / HUD optics – Inject red graphics cleanly, with negligible blue-green bleed toward the viewer.
Need rapid prototypes or high-volume supply? R2918 filters can be coated, diced, and shipped to your exact specifications—fast.
