HM-745 Hot Mirror & UV-IR Cut Filter

The HM-745 is the broadest hot mirror in the standard lineup, with a 50 % cutoff at 746 nm and peak transmission of 95.6 % at 706 nm. It passes visible light from 412 nm to 746 nm, capturing the widest possible red and near-IR content while still maintaining infrared rejection. However, this comes with a tradeoff: blue transmission drops to 77.8 % (lower than other HM models), reflecting a gradual blue onset at 412 nm. Green (93.3 %), yellow (94.4 %), and red (94.9 %) all exceed 93 %. NIR(700-850) transmission reaches 31.4 %-higher than other HM filters-making HM-745 appropriate for applications where some early NIR penetration is acceptable or even desired.

Key Advantages

• Widest visible-pass range - Extends to 746 nm, the broadest HM cutoff available, allowing maximum red and Si-sensor-range light to reach the target while blocking deep thermal IR.
• Controlled blue rolloff - Blue transmission begins at 412 nm with gradual onset (77.8 %), which is ideal for applications where blue noise or UV stray light is a concern but red/NIR data is critical.
• Hard-oxide ion-assisted coating - Advanced durability coating resists thermal cycling, mechanical stress, and long-term high-power light exposure without optical performance degradation.
• High-transmission red and NIR - Red (94.9 %) and early NIR (31.4 % in 700-850 nm) allow imaging systems to leverage near-infrared information for range, material analysis, or thermal measurement.
• Broad substrate and custom format availability - Round, square, and free-form blanks from 5 mm to 450 mm diameter, thickness 0.21-3.8 mm, on Borofloat, soda-lime, Schott D263 T, or Corning Eagle XG substrates.

Typical Applications

• NIR and multi-spectral imaging - The extended pass to 746 nm with 31 % early-NIR transmission supports multi-spectral inspection, precision agriculture, and material characterization without deep-IR thermal noise.
• Range and depth sensing - Allows structured-light and time-of-flight depth sensors to operate using red and NIR LEDs while rejecting thermal background from the environment.
• High-brightness projection systems - Maximum visible and near-IR pass supports high-lumens projection with controlled thermal management, ideal for outdoor and high-ambient-light venues.
• Machine vision with NIR illumination - Permits NIR lighting systems to contribute to imaging while blocking ambient thermal radiation, enabling contrast enhancement in poor-lighting factory environments.
• Emerging autonomous sensing platforms - The broad spectral pass supports next-generation autonomous-vehicle LiDAR systems, autonomous drones, and robotics that require both visible and near-IR environmental sensing.

KUPO Optics manufactures HM-745 in fully custom configurations-your choice of size, shape, thickness, and substrate-with rapid prototype and production timelines.