CM-740 Cold Mirror & Longpass Filter
Separate visible light from near-infrared while preserving red wavelengths for dual-band imaging.
- Reflection band (visible): 380 – 726 nm, ≥ 90.9 % R
- Passband (IR): 745 – 1200 nm, 80.4 – 97.9 % T
- Cut-on (T50): ≈ 739 nm
- Edge steepness: ~23 nm (10 → 90 % transition)
- Visible leakage: < 9.1 % T across 380 – 726 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
CM-740 Hybrid delivers Reflection band (visible) 380 – 726 nm, ≥ 90.9 % R, Passband (IR) 745 – 1200 nm, 80.4 – 97.9 % T, and Cut-on (T50) ≈ 739 nm.
The hard-oxide coating is built for repeated handling, heat, and cleaning.
Best suited for:
Separate visible light from near-infrared while preserving red wavelengths for dual-band imaging.
Description
The CM-740 is a foundational cold mirror delivering complete visible suppression paired with exceptional infrared transmission across the near and shortwave infrared bands. The 50 % cut-on point sits at 739 nm, with peak transmission of 97.9 % at 884 nm. Visible light extinction is near-total (UV 0.4 %, blue 0.1 %, green 0.2 %, red 0.3 %), while NIR (700-850 nm) reaches 71.1 %, NIR (850-1000 nm) climbs to 95.1 %, and SWIR (1000-1200 nm) sustains 94.5 %. This flat, high-transmission profile across the infrared spectrum makes the CM-740 the standard workhorse for applications requiring clean separation of visible light from thermal radiation.
Key Advantages
- Complete Visible Rejection - Blocks all visible wavelengths below 739 nm with extinction exceeding 99.5 %, ensuring zero visible-light contamination in IR detection systems
- Flat NIR-SWIR Transmission - Maintains > 94 % transmission from 850 nm through 1200 nm, enabling reliable thermal imaging and multi-spectral IR sensing without gain compensation
- Durable Hard-Oxide Coating - Ion-assisted hard-oxide design withstands abrasive environments, thermal cycling, and mechanical contact without performance degradation
- Flexible Substrate Options - Available in custom formats from 5 mm to 450 mm diameter, round and square apertures, free-form blanks, and 0.21-3.8 mm thickness on Borofloat, soda-lime, Schott D263 T, or Corning Eagle XG
- Rapid Prototyping & Scale - Mature coating process supports both single prototypes and production runs without engineering delays
Typical Applications
- Thermal Camera Optics - Directs infrared from thermal scenes onto sensor arrays while blocking visible ambient light and stray photons that degrade image contrast
- LED + IR Illumination - Separates visible illumination from IR emitters in mixed-light surveillance and machine vision, maintaining spectral isolation across both bands
- Projection System Cooling - Extracts waste heat from projection engines and display optics, protecting downstream optical components from thermal damage
- Scientific Spectroscopy - Enables simultaneous visible-light diagnostics and thermal monitoring in combustion analysis, plasma research, and materials characterization
- Automotive Thermal Management - Directs engine and cabin thermal radiation toward cooling systems while preventing visible glare contamination in driver-assistance sensors
The CM-740 is production-ready and ideal for OEMs seeking immediate deployment. We support rapid prototyping with sample quantities or transition to volume production with minimal lead time.
FAQ
CM-740 FAQ
What is CM-740 and what is it used for?
CM-740 is a Broadband Visible-Blocking Cold Mirror for General-Purpose Heat Separation. The CM-740 is a foundational cold mirror delivering complete visible suppression paired with exceptional infrared transmission across the near and shortwave infrared bands. The 50 % cut-on point sits at 739 nm, with peak transmission of 97.9 % at 884 nm. Common uses include Thermal Camera Optics, LED + IR Illumination, Projection System Cooling, and Scientific Spectroscopy.
What are the key optical specs of CM-740?
Key published specs for CM-740 include Reflection band (visible): 380 – 726 nm, ≥ 90.9 % R; Passband (IR): 745 – 1200 nm, 80.4 – 97.9 % T; Cut-on (T50): ≈ 739 nm; Edge steepness: ~23 nm (10 → 90 % transition); Visible leakage: < 9.1 % T across 380 – 726 nm.
What applications is CM-740 best suited for?
CM-740 is commonly used for Thermal Camera Optics, LED + IR Illumination, Projection System Cooling, and Scientific Spectroscopy. Thermal Camera Optics - Directs infrared from thermal scenes onto sensor arrays while blocking visible ambient light and stray photons that degrade image contrast.
Can CM-740 be customized for size, substrate, or coating requirements?
KUPO lists the construction for CM-740 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. Flexible Substrate Options - Available in custom formats from 5 mm to 450 mm diameter, round and square apertures, free-form blanks, and 0.21-3.8 mm thickness on Borofloat, soda-lime, Schott D263 T, or Corning Eagle XG.
What should I know about angle of incidence and durability for CM-740?
The published angle of incidence for CM-740 is 0° (normal incidence); custom angles available. The hard-oxide coating is built for repeated handling, heat, and cleaning.
