BH-A09 Dichroic Beamsplitter / Red Reflector

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.