HM-635 Hot Mirror & UV-IR Cut Filter
Block near-infrared heat aggressively from the red edge inward, maximizing thermal suppression in compact systems.
- Passband (visible): 402–620 nm, 85.1–94.4 % T
- Cut-off (T50): ≈ 635 nm
- Edge steepness: ~38 nm (90 → 10 % transition)
- IR rejection: < 0.5 % T from 701–1023 nm (OD ≥ 1.3)
- 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 IR blocking range, 45° AOI for beam-steering, rapid prototypes
Learn more
HM-635 Hybrid delivers Passband (visible) 402–620 nm, 85.1–94.4 % T, Cut-off (T50) ≈ 635 nm, and Edge steepness ~38 nm (90 → 10 % transition).
The hard-oxide coating is built for repeated handling, heat, and cleaning.
Best suited for:
Thermal camera protection filters, blue-channel photography, compact UV-VIS spectrometers, precision thermal sensors, cooled detector pre-filters, heat-sensitive scientific instruments.
Description
The HM-635 is the most aggressive short-cutoff hot mirror, cutting visible transmission at 635 nm (50 % crossover) with peak performance of 94.4 % at 559 nm. It passes blue (91.7 %) and green (93.7 %) powerfully but aggressively clips yellow and red: yellow reaches 93.3 % while red plummets to 32.8 %. Unusually for a hot mirror, HM-635 permits significant UV pass-through (15.9 %)-a feature that opens unique applications requiring simultaneous UV and green-blue illumination. SWIR(1000-1200) transmission reaches 45 %, creating another transparency window in the short-wave infrared band, making HM-635 suitable for dual-band UV-visible-SWIR applications.
Key Advantages
- Strong blue-green with UV transmission - Blue (91.7 %), green (93.7 %), and UV (15.9 %) all pass efficiently, enabling simultaneous UV and visible illumination in a single optical path for fluorescence and dual-spectrum imaging.
- Aggressive red and yellow suppression - Red transmission drops to 32.8 % and yellow to 93.3 %, effectively eliminating red-light contamination for applications requiring pure blue-green environmental control.
- Hard-oxide ion-assisted coating - Robust optical coating with UV and thermal stability, designed to withstand UV exposure, thermal stress, and long-term operational use without performance loss.
- SWIR transparency window - The 45 % SWIR(1000-1200) transmission enables simultaneous visible and short-wave-infrared sensing, useful for multi-spectral and thermal applications.
- Versatile custom format options - 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.
Typical Applications
- Fluorescence microscopy and imaging - UV pass-through combined with blue-green transmission enables simultaneous excitation and emission wavelength imaging without requiring multiple filter turrets or sequential acquisition.
- UV curing and inspection - Passes UV illumination for curing processes while blue-green light enables real-time visual inspection and alignment monitoring without switching optical paths.
- Dual-spectrum material analysis - The combination of UV-visible pass-through and 45 % SWIR transparency supports multi-wavelength material characterization and defect detection in industrial quality assurance.
- Gemstone and art authentication - UV-visible fluorescence combined with SWIR reflectance allows experts to authenticate precious stones and artworks using multiple spectral signatures in one measurement.
- Specialized research applications - Unique dual-band capability (UV-visible-SWIR) supports photochemistry, materials science, and advanced spectroscopy where multi-wavelength information is diagnostic.
KUPO Optics manufactures HM-635 in full custom specifications-your choice of size, shape, thickness, and substrate-with rapid prototyping and high-volume production.
FAQ
HM-635 FAQ
What is HM-635 and what is it used for?
HM-635 is a Aggressive Short-Wave Cutoff with UV and SWIR Pass-Through. The HM-635 is the most aggressive short-cutoff hot mirror, cutting visible transmission at 635 nm (50 % crossover) with peak performance of 94.4 % at 559 nm. It passes blue (91.7 %) and green (93.7 %) powerfully but aggressively clips yellow and red: yellow reaches 93.3 % while red plummets to 32.8 %. Common uses include Fluorescence microscopy and imaging, UV curing and inspection, Dual-spectrum material analysis, and Gemstone and art authentication.
What are the key optical specs of HM-635?
Key published specs for HM-635 include Passband (visible): 402–620 nm, 85.1–94.4 % T; Cut-off (T50): ≈ 635 nm; Edge steepness: ~38 nm (90 → 10 % transition); IR rejection: < 0.5 % T from 701–1023 nm (OD ≥ 1.3); AOI: 0° (normal incidence); custom angles available.
What applications is HM-635 best suited for?
HM-635 is commonly used for Fluorescence microscopy and imaging, UV curing and inspection, Dual-spectrum material analysis, and Gemstone and art authentication. Fluorescence microscopy and imaging - UV pass-through combined with blue-green transmission enables simultaneous excitation and emission wavelength imaging without requiring multiple filter turrets or sequential acquisition.
Can HM-635 be customized for size, substrate, or coating requirements?
KUPO lists the construction for HM-635 as Ion-assisted hard-oxide; 5–450 mm shapes, 0.21–3.8 mm thick. Published custom options include Edge tuning, extended IR blocking range, 45° AOI for beam-steering, rapid prototypes. Versatile custom format options - 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.
What should I know about angle of incidence and durability for HM-635?
The published angle of incidence for HM-635 is 0° (normal incidence); custom angles available. The hard-oxide coating is built for repeated handling, heat, and cleaning.
