BH-A09 Dichroic Beamsplitter / Red Reflector

Dichroic splitter for 45 ° AOI: passes 410 – 525 nm blue-green while reflecting > 98 % of 610 – 740 nm red—perfect for colour-clean beam routing.

  • AOI design: 45 ° (spectral shift < 5 nm for 40–50 °)
  • Pass window: < 5 % R from 410 – 525 nm (cyan-green)
  • Reflect band: ≥ 98 % R 610 – 740 nm (red plateau)
  • Edge steepness: 10 – 90 % transition ≈ 50 nm
  • Wavefront: λ/10 P-V @ 632 nm (1″ aperture)
  • Durability: IBS stack meets MIL-M-13508C (adhesion / abrasion / humidity)
  • Formats: 5 – 450 mm, 0.5 – 3 mm on Borofloat®, Eagle XG, D 263 T, fused silica
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BH-A09 is KUPO’s precision blue-green pass / red mirror coating for 45 ° incidence. Reflectance plunges below 5 % between 410 nm and 525 nm, letting cyan-green light race through with virtually no loss. Just 65 nm farther into the spectrum the curve rockets past 90 % and settles above 98 % from 610 nm to 740 nm, providing a near-lossless reflector for red lasers, LEDs, or broadband sources. Steeper slopes at both edges keep colour cross-talk below 1 %, ideal for dual-path fluorescence microscopes, RGB projection engines, and laser beam combiners.

The dense ion-beam-sputtered stack shrugs off solvents, humidity, and thermal cycling while maintaining batch-to-batch spectral repeatability within ± 2 nm. Standard substrates include Borofloat®, Corning Eagle XG, Schott D 263 T, and fused silica, sized up to 450 mm with thicknesses from 0.5 mm to 3 mm. Options such as back-side AR, wedged blanks, or edge-shift tuning ship in as little as ten days for prototype runs.

Typical uses: split red emission from cyan/green excitation in fluorescence, merge 633 nm He-Ne with 488 nm argon lines in multi-colour laser rigs, isolate red channels in RGB projectors, or redirect NIR heat away from sensitive sensors while passing visible light to the detector.

$88,888.00

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Description

BH-A09 is KUPO Optics’ high-performance dichroic coating engineered for precise color separation and spectral management. This multi-layer dielectric filter is designed to efficiently transmit light in the blue-green region of the spectrum while serving as a highly reflective mirror for red and near-infrared wavelengths. It is the ideal solution for applications requiring the splitting of a light source into distinct color paths or the removal of red-band energy from a system.

At a 45° angle of incidence, the BH-A09 coating creates a wide transmission window, with reflectance dropping below 5% for all wavelengths between approximately 410 nm and 525 nm. The performance curve then transitions steeply, with reflectance rocketing past 90% at 590 nm and remaining above 98% across a broad plateau from 610 nm to 740 nm. Beyond this band, reflectance rolls off again in the near-IR. The result is a clean, efficient split, passing cyan-green light while powerfully redirecting the red portion of the spectrum.

Key Advantages

  • High-Fidelity Color Separation – A sharp spectral transition between the transmission and reflection bands ensures minimal color cross-contamination and high-purity output beams.

  • Exceptional Red-Band Reflection – Over 98% reflectance in the critical 610–740 nm range allows for near-lossless redirection of red lasers, LEDs, and filtered light sources.

  • Broad Blue-Green Transmission – The wide, low-reflectance passband from 410 nm to 525 nm allows for maximum throughput of desired cyan and green wavelengths.

  • Durable, Stable Performance – A hard, dense dielectric coating provides excellent resistance to environmental factors and repeated cleaning, ensuring a long and reliable service life.

  • Low-Scatter, High-Quality Substrate – Built on a precision-polished, λ/10 substrate, the BH-A09 maintains wavefront integrity for imaging, laser, and sensor applications.

  • Rapid Customisation – KUPO stocks standard sizes for immediate prototyping, and our engineers can rapidly develop custom shapes, substrates, or performance-tuned designs to meet your specific needs.

Typical Applications

  • Fluorescence Microscopy & Instrumentation – Separate longer-wavelength red emission signals from shorter-wavelength cyan/green excitation light with high efficiency.

  • Laser Beam Combining & Splitting – Merge or divide red laser lines (e.g., HeNe at 633 nm) with argon-ion or other blue/green lasers in multi-wavelength systems.

  • RGB Projection & Display Systems – Isolate the red channel from blue and green channels in a light engine, improving color purity and contrast.

  • Entertainment & Laser Shows – Used as a primary color filter or splitter to create vivid, saturated red effects from a broadband white light source.

  • Photometry & Colorimetry – Isolate distinct spectral regions to enable precise measurement and analysis with dedicated sensors.

Need to fine-tune the cut-on wavelength, add an anti-reflection coating to the back surface, or integrate this coating into a larger optical assembly? Talk to KUPO Optics today—our engineering team can tailor BH-A09 to your optical path and ship prototype parts fast.

 

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