BH-A50 Hot Mirror & UV-IR Cut Filter

The BH-A50 is a premium hot mirror engineered for extended near- and short-wave infrared blocking, with a 50 % cutoff at 713 nm and peak transmission of 94.2 % at 685 nm. It passes visible light across the full spectrum from 411 nm to 713 nm with solid fidelity: blue reaches 76.4 % (slightly lower, reflecting a steeper blue edge), green (90.3 %), yellow (91.5 %), and red (92.8 %) all perform well. The critical distinction is extended infrared rejection: NIR(700-850) drops to 9.8 %, NIR(850-1000) to 2 %, and blocking extends reliably through 1500 nm. BH-A50 is designed for high-power applications, thermal-sensitive instruments, and systems requiring definitive IR suppression across a broader wavelength span.

Key Advantages

• Extended IR blocking to 1500 nm - Deep and sustained NIR rejection (9.8 % at 700-850 nm, 2 % at 850-1000 nm) with blocking that extends reliably beyond 1500 nm. Protects optical systems from thermal radiation across a wider spectrum than standard hot mirrors.
• Clean visible transmission - Passes 411-713 nm with blue (76.4 %), green (90.3 %), yellow (91.5 %), and red (92.8 %) providing reliable color fidelity across the visible spectrum.
• Hard-oxide ion-assisted coating - Premium durable coating engineered for high-power optical systems, thermal cycling, mechanical stress, and extended operational life without transmission drift or degradation.
• Controlled blue rolloff - Blue transmission begins at 411 nm with a steeper onset (76.4 %) compared to broader HM filters, useful for applications where blue noise must be minimized.
• Complete custom format options - Round, square, 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

• High-power laser and light source protection - Extended IR blocking beyond 1500 nm protects sensitive optics and sensors in high-power laser systems, theatrical lighting, and industrial illumination from cumulative thermal damage.
• Long-range thermal imaging protection - The comprehensive IR rejection from 700-1500 nm shields infrared imaging sensors from stray thermal radiation, improving image contrast and measurement accuracy.
• Medical and surgical high-brightness systems - Extended IR blocking protects sensitive biological tissue and surgical site sensors from thermal radiation generated by high-intensity surgical and diagnostic lighting.
• Spectroscopy and analytical instrumentation - The broad IR suppression (to 1500 nm) eliminates thermal noise across extended wavelength ranges used in FTIR, Raman, and advanced analytical techniques.
• Precision metrology and measurement - Extended IR blocking ensures stable, thermal-noise-free measurements in precision instruments used for dimensional metrology, optical testing, and scientific measurement.

KUPO Optics manufactures BH-A50 hot mirrors in custom specifications-diameter, shape, thickness, and substrate of your choice-with rapid prototyping and full production support.