HM-690 Hot Mirror & UV-IR Cut Filter
Achieve aggressive infrared rejection while retaining mid-red and visible sensitivity for thermal-sensitive applications.
- Passband (visible): 415–673 nm, 86.1–96.0 % T
- Cut-off (T50): ≈ 688 nm
- Edge steepness: ~46 nm (90 → 10 % transition)
- IR rejection: < 0.5 % T from 728–896 nm (OD ≥ 1.3)
- 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 IR blocking range, 45° AOI for beam-steering, rapid prototypes
Learn more
HM-690 Hybrid delivers Passband (visible) 415–673 nm, 86.1–96.0 % T, Cut-off (T50) ≈ 688 nm, and Edge steepness ~46 nm (90 → 10 % transition).
The hard-oxide coating is built for repeated handling, heat, and cleaning.
Best suited for:
High-speed camera protection, sensor thermal management, precision measurement optics, scientific thermal imaging, heat-sensitive detector filters, industrial vision with incandescent or halogen light sources.
Description
The HM-690 cuts off the visible spectrum aggressively at 688 nm (50 % crossover), with peak transmission of 96 % at 588 nm. It passes blue (85 %), green (94.3 %), and yellow (95.6 %) strongly but clips red to 83.1 %-a significant compromise for applications where red light must be suppressed. The distinctive feature of HM-690 is its NIR leakage window: transmission in the 850-1000 nm band rises to 32.9 %, and SWIR(1000-1200) reaches 57.8 %. This is not a clean IR blocker, but rather a selective filter designed for applications where green-yellow illumination is desired and NIR transparency is either unavoidable or functionally useful.
Key Advantages
- Sharp green-yellow pass - Transmission peaks at 588 nm in the yellow-green region with 95 % efficiency. Ideal for applications requiring monochromatic or yellow-dominant illumination while minimizing red cross-talk.
- Controlled red suppression - Red transmission limited to 83 % eliminates red channel contamination in applications such as specific industrial inspection, laser work, or wavelength-selective imaging.
- Hard-oxide ion-assisted coating - Durable, thermally stable coating maintains optical performance through thermal stress and repeated high-intensity light exposure in demanding industrial applications.
- Transparent NIR window - The unusual 850-1200 nm transmission window (33-58 %) allows NIR sensing, thermal measurement, or NIR illumination to coexist with visible-light systems without blocking IR information.
- Custom sizes and substrate options - Available in round, square, and free-form shapes from 5 mm to 450 mm diameter, thickness 0.21-3.8 mm, on Borofloat, soda-lime, Schott D263 T, or Corning Eagle XG.
Typical Applications
- Green and yellow laser applications - Suppresses red and NIR interference while passing green-yellow laser light efficiently, ideal for laser show, medical laser, and industrial laser marking systems.
- Dual-spectrum imaging - Permits simultaneous visible (green-yellow) and NIR sensing in a single optical path, supporting applications in precision agriculture, materials inspection, and thermal profiling.
- Industrial defect detection - Yellow-dominant illumination reduces unwanted red-light glint while the NIR window allows infrared thermal signatures to be captured independently, improving defect classification.
- Thermal monitoring with visible guidance - Green-yellow light guides operator vision while the transparent NIR window allows thermal imaging sensors to measure surface temperature without visible-light saturation.
- Specialized scientific instrumentation - Wavelength-selective filtering with dual-band capability supports hyperspectral research and specialized spectroscopy where green-yellow and NIR data must be collected separately.
KUPO Optics custom-manufactures HM-690 in your exact specifications-diameter, shape, thickness, and substrate choice-with rapid prototyping and full production capability.
FAQ
HM-690 FAQ
What is HM-690 and what is it used for?
HM-690 is a Tight Visible Cutoff with NIR Leakage Window. The HM-690 cuts off the visible spectrum aggressively at 688 nm (50 % crossover), with peak transmission of 96 % at 588 nm. It passes blue (85 %), green (94.3 %), and yellow (95.6 %) strongly but clips red to 83.1 %-a significant compromise for applications where red light must be suppressed. Common uses include Green and yellow laser applications, Dual-spectrum imaging, Industrial defect detection, and Thermal monitoring with visible guidance.
What are the key optical specs of HM-690?
Key published specs for HM-690 include Passband (visible): 415–673 nm, 86.1–96.0 % T; Cut-off (T50): ≈ 688 nm; Edge steepness: ~46 nm (90 → 10 % transition); IR rejection: < 0.5 % T from 728–896 nm (OD ≥ 1.3); AOI: 0° (normal incidence); custom angles available.
What applications is HM-690 best suited for?
HM-690 is commonly used for Green and yellow laser applications, Dual-spectrum imaging, Industrial defect detection, and Thermal monitoring with visible guidance. Green and yellow laser applications - Suppresses red and NIR interference while passing green-yellow laser light efficiently, ideal for laser show, medical laser, and industrial laser marking systems.
Can HM-690 be customized for size, substrate, or coating requirements?
KUPO lists the construction for HM-690 as Ion-assisted hard-oxide; 5–450 mm shapes, 0.21–3.8 mm thick. Published custom options include Edge tuning, extended IR blocking range, 45° AOI for beam-steering, rapid prototypes. Transparent NIR window - The unusual 850-1200 nm transmission window (33-58 %) allows NIR sensing, thermal measurement, or NIR illumination to coexist with visible-light systems without blocking IR information.
What should I know about angle of incidence and durability for HM-690?
The published angle of incidence for HM-690 is 0° (normal incidence); custom angles available. The hard-oxide coating is built for repeated handling, heat, and cleaning.
