CM-618 Cold Mirror & Longpass Filter
Reflect most visible light and transmit deep into NIR and SWIR for true broadband infrared detection.
- Reflection band (visible): 380 – 595 nm, ≥ 90.4 % R
- Passband (IR): 701 – 1200 nm, 88.7 – 100.6 % T
- Cut-on (T50): ≈ 617 nm
- Edge steepness: ~38 nm (10 → 90 % transition)
- Visible leakage: < 9.6 % T across 380 – 595 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-618 Hybrid delivers Reflection band (visible) 380 – 595 nm, ≥ 90.4 % R, Passband (IR) 701 – 1200 nm, 88.7 – 100.6 % T, and Cut-on (T50) ≈ 617 nm.
The hard-oxide coating is built for repeated handling, heat, and cleaning.
Best suited for:
Reflect most visible light and transmit deep into NIR and SWIR for true broadband infrared detection.
Description
The CM-618 is a rare broadband mirror that challenges conventional cold-mirror boundaries: it passes visible red light alongside the entire infrared spectrum. The 50 % cut-on point is exceptionally early at 617 nm, with peak transmission of 100.6 % at 879 nm (instrumental super-unity likely reflects calibration optimality). Visible extinction is minimal in the red region (81.8 %), moderate in yellow (5.0 %), and excellent in shorter wavelengths (UV 0.4 %, blue 0.7 %, green 0.8 %). The infrared performance is extraordinary: NIR (700-850 nm) transmits 99.2 %, NIR (850-1000 nm) reaches 99.0 %, and SWIR (1000-1200 nm) sustains 91.0 %. This filter uniquely bridges red-light and thermal applications in a single optic.
Key Advantages
- Near-Unity NIR Transmission - > 99 % transmission across 700-1000 nm minimizes optical losses in multi-stage thermal and spectroscopic systems
- Red-Light + Infrared Integration - 81.8 % red passthrough combined with near-perfect IR pass enables red-laser alignment, target marking, and thermal imaging in unified optical paths
- Minimal Green-Blue Blocking - Selective band rejection (green 0.8 %, blue 0.7 %) removes only the shortest visible wavelengths, allowing flexible optical designs
- Ion-Assisted Hard-Oxide Robustness - Durable coating design resists environmental contamination, thermal gradients, and mechanical contact without performance loss
- Custom Formats & Material Selection - Available from 5 mm to 450 mm diameter in round, square, and free-form apertures on Borofloat, soda-lime, Schott D263 T, or Corning Eagle XG
Typical Applications
- Broadband Thermal + Red-Laser Systems - Integrates infrared thermal imaging with red-laser targeting, guidance, or alignment in single optical assembly without secondary dichroic elements
- Industrial Furnace Monitoring - Transmits red control light and process-diagnostic beams while capturing full thermal spectrum for temperature mapping and anomaly detection
- Advanced Medical Thermal Imaging - Enables red-wavelength surgical guidance, laser therapy delivery, and thermal tissue diagnostics in integrated clinical instruments
- Broadband Spectroscopy - Passes red calibration sources alongside infrared signal in multi-modal analysis of materials, gases, and thermal phenomena
- Emerging Hyperspectral Sensing - Facilitates simultaneous red-light and IR data collection for environmental monitoring, agricultural assessment, and object recognition
The CM-618 is ideal for engineers designing integrated thermal-plus-visible systems with minimal optical complexity. We prototype custom apertures quickly and support high-volume manufacturing.
FAQ
CM-618 FAQ
What is CM-618 and what is it used for?
CM-618 is a Ultra-Broadband Warm-Pass Mirror for Red-Extended and Full-Infrared Transmission. The CM-618 is a rare broadband mirror that challenges conventional cold-mirror boundaries: it passes visible red light alongside the entire infrared spectrum. The 50 % cut-on point is exceptionally early at 617 nm, with peak transmission of 100.6 % at 879 nm (instrumental super-unity likely reflects calibration optimality). Common uses include Broadband Thermal + Red-Laser Systems, Industrial Furnace Monitoring, Advanced Medical Thermal Imaging, and Broadband Spectroscopy.
What are the key optical specs of CM-618?
Key published specs for CM-618 include Reflection band (visible): 380 – 595 nm, ≥ 90.4 % R; Passband (IR): 701 – 1200 nm, 88.7 – 100.6 % T; Cut-on (T50): ≈ 617 nm; Edge steepness: ~38 nm (10 → 90 % transition); Visible leakage: < 9.6 % T across 380 – 595 nm.
What applications is CM-618 best suited for?
CM-618 is commonly used for Broadband Thermal + Red-Laser Systems, Industrial Furnace Monitoring, Advanced Medical Thermal Imaging, and Broadband Spectroscopy. Broadband Thermal + Red-Laser Systems - Integrates infrared thermal imaging with red-laser targeting, guidance, or alignment in single optical assembly without secondary dichroic elements.
Can CM-618 be customized for size, substrate, or coating requirements?
KUPO lists the construction for CM-618 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. Custom Formats & Material Selection - Available from 5 mm to 450 mm diameter in round, square, and free-form apertures on Borofloat, soda-lime, Schott D263 T, or Corning Eagle XG.
What should I know about angle of incidence and durability for CM-618?
The published angle of incidence for CM-618 is 0° (normal incidence); custom angles available. The hard-oxide coating is built for repeated handling, heat, and cleaning.
