BH-A29 Cold Mirror & Longpass Filter
Smooth, gradual visible-to-infrared transition for applications tolerant of broader spectral roll-off.
- Reflection band (visible): 380 – 684 nm, ≥ 90.2 % R
- Passband (IR): 747 – 1200 nm, 80.9 – 95.8 % T
- Cut-on (T50): ≈ 722 nm
- Edge steepness: ~75 nm (10 → 90 % transition)
- Visible leakage: < 9.8 % T across 380 – 684 nm
- AOI: 0° (normal incidence); custom angles available
- Construction: Ion-assisted hard-oxide; 5 – 450 mm shapes, 0.21 – 3.8 mm thick
- Custom options: Edge tuning, extended reflection band, custom AOI, rapid prototypes
Learn more
BH-A29 Hybrid delivers Reflection band (visible) 380 – 684 nm, ≥ 90.2 % R, Passband (IR) 747 – 1200 nm, 80.9 – 95.8 % T, and Cut-on (T50) ≈ 722 nm.
The hard-oxide coating is built for repeated handling, heat, and cleaning.
Best suited for:
Smooth, gradual visible-to-infrared transition for applications tolerant of broader spectral roll-off.
Description
The BH-A29 brings an unusually early 50 % cut-on at 722 nm, allowing selective red-light transmission while blocking blue and green entirely. Peak transmission reaches 95.8 % at 1025 nm, deep in the shortwave-infrared. The visible spectrum shows UV 0.9 %, blue 0.7 %, green 0.7 %, but red transmission is substantial at 4.3 %, enabling simultaneous red-light imaging and thermal IR capture. NIR (700-850 nm) transmits 77.2 %, NIR (850-1000 nm) reaches 94.5 %, and SWIR (1000-1200 nm) sustains 94.5 %. This unique profile bridges visible and infrared modalities in single-optics solutions.
Key Advantages
- Red-Light Passthrough Capability - 4.3 % red transmission enables simultaneous red-light alignment, laser-aiming, or visible target acquisition alongside IR thermal imaging
- Broad Green-to-Blue Blocking - Attenuates green (0.7 %) and blue (0.7 %) while passing red, creating a narrow visible-light window for specialized hybrid sensor designs
- Peak SWIR Performance - 95.8 % peak transmission at 1025 nm with flat > 94 % pass across the full shortwave-infrared band for high-sensitivity thermal detection
- Rugged Hard-Oxide Coating - Ion-assisted deposition ensures resistance to thermal cycling, dust, and mechanical stress in field-deployed optical systems
- Custom Apertures & Substrates - Manufactured as round, square, and free-form blanks from 5 mm to 450 mm on Borofloat, soda-lime, Schott D263 T, or Corning Eagle XG
Typical Applications
- Multi-Modal Thermal Surveillance - Combines red laser designation and visible targeting with background thermal imaging in advanced security and military optics
- Medical Thermal Diagnostics - Enables red-light guidance for endoscopic thermal imaging, perfusion monitoring, and tissue temperature assessment in clinical instruments
- Automotive Driver-Assistance Fusion - Integrates visible red tail-light recognition with thermal-IR collision avoidance in next-generation ADAS systems
- Scientific Spectral Decomposition - Isolates red-channel behavior in dual-band or multi-modal optical experiments combining visible and thermal datasets
- Emerging AR/VR Thermal Overlays - Blends visible red markers with thermal background layers for augmented-reality thermal visualization and heads-up displays
The BH-A29 opens new possibilities for integrated visible-IR systems. Our team can prototype hybrid designs rapidly and scale production to match your volume requirements.
FAQ
BH-A29 FAQ
What is BH-A29 and what is it used for?
BH-A29 is a Early-Cutoff Broadband Pass for Red-Extended Thermal Imaging and Visible-NIR Hybrid Systems. The BH-A29 brings an unusually early 50 % cut-on at 722 nm, allowing selective red-light transmission while blocking blue and green entirely. Peak transmission reaches 95.8 % at 1025 nm, deep in the shortwave-infrared. Common uses include Multi-Modal Thermal Surveillance, Medical Thermal Diagnostics, Automotive Driver-Assistance Fusion, and Scientific Spectral Decomposition.
What are the key optical specs of BH-A29?
Key published specs for BH-A29 include Reflection band (visible): 380 – 684 nm, ≥ 90.2 % R; Passband (IR): 747 – 1200 nm, 80.9 – 95.8 % T; Cut-on (T50): ≈ 722 nm; Edge steepness: ~75 nm (10 → 90 % transition); Visible leakage: < 9.8 % T across 380 – 684 nm.
What applications is BH-A29 best suited for?
BH-A29 is commonly used for Multi-Modal Thermal Surveillance, Medical Thermal Diagnostics, Automotive Driver-Assistance Fusion, and Scientific Spectral Decomposition. Multi-Modal Thermal Surveillance - Combines red laser designation and visible targeting with background thermal imaging in advanced security and military optics.
Can BH-A29 be customized for size, substrate, or coating requirements?
KUPO lists the construction for BH-A29 as Ion-assisted hard-oxide; 5 – 450 mm shapes, 0.21 – 3.8 mm thick. Published custom options include Edge tuning, extended reflection band, custom AOI, rapid prototypes. Custom Apertures & Substrates - Manufactured as round, square, and free-form blanks from 5 mm to 450 mm on Borofloat, soda-lime, Schott D263 T, or Corning Eagle XG.
What should I know about angle of incidence and durability for BH-A29?
The published angle of incidence for BH-A29 is 0° (normal incidence); custom angles available. The hard-oxide coating is built for repeated handling, heat, and cleaning.
