HM-725 Hot Mirror & UV-IR Cut Filter

The HM-725 extends visible transmission deeper into the red-to-NIR boundary, with a 50 % crossover at 732 nm while maintaining excellent visible fidelity across 405-732 nm. Peak transmission is 95.4 % at 691 nm, with blue at 86.6 %, green at 93.7 %, yellow at 94.7 %, and red at 94.8 %. The critical advantage is extended red content-ideal for applications where red wavelengths carry diagnostic or quality-assurance information. NIR blocking is equally decisive: transmission drops to 23 % in the 700-850 nm band and falls to 0.1 % above 850 nm.

Key Advantages

• Extended red transmission - Passes visible light to 732 nm, capturing an additional 18 nm of red content compared to HM-710. Essential for applications where red spectral information is diagnostic.
• Deep NIR rejection - NIR(850-1000) transmission falls to 0.1 %, providing aggressive thermal blocking that protects sensors and optics while the extended cutoff preserves color-critical red wavelengths.
• Hard-oxide ion-assisted coating - Durable, thermally stable coating designed to survive high-power light sources and temperature cycling without optical degradation or delamination.
• Smooth transition profile - The gradual rolloff from 700-850 nm provides predictable IR blocking behavior in imaging systems using spectrally dispersed light.
• Custom sizes and substrates - Round, square, and free-form shapes from 5 mm to 450 mm, with thickness 0.21-3.8 mm on Borofloat, soda-lime, Schott D263 T, or Corning Eagle XG.

Typical Applications

• Medical imaging and endoscopy - Passes red and near-red wavelengths crucial for tissue visualization while blocking thermal noise from surgical lighting.
• Quality assurance and color imaging - Preserves full red spectrum for accurate color-based defect detection and quality grading in manufacturing environments.
• High-brightness display and projection - Extended red pass ensures vivid red and magenta hues in cinema and large-venue projection systems with thermal management.
• Thermal landscape observation - Blocks deep thermal bands while preserving visible-light landscape observation, useful in outdoor surveillance and environmental monitoring.
• Instrumentation and spectroscopy - Allows broader visible-spectrum analysis without thermal noise, supporting research in materials science and spectroscopic measurement.

KUPO Optics manufactures HM-725 in rapid prototyping cycles with full customization of diameter, shape, thickness, and substrate material for both lab evaluation and production deployment.