B70704 Shortpass Filter
Cyan rejection for blue-green channel splitting and colour-accurate optical systems.
- Passband: 419 – 457 nm, 90.1 – 91.7 % T (± 0.8 % ripple)
- Cut-off (T50): ≈ 469 nm
- Edge steepness: ~24 nm (90 → 10 % transition)
- Blocking: < 0.98 % T above 507 nm (OD ≥ 2)
- 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, ripple smoothing, 45° AOI, rapid prototypes
Learn more
B70704 Hybrid delivers Passband 419 – 457 nm, 90.1 – 91.7 % T (± 0.8 % ripple), Cut-off (T50) ≈ 469 nm, and Edge steepness ~24 nm (90 → 10 % transition).
The hard-oxide coating is built for repeated handling, heat, and cleaning.
Best suited for:
Blue LED light sources, display calibration, machine vision blue channels, spectroscopic instruments.
Description
The B70704 passes the deep-blue and blue spectrum with its 50 % cut-off measured at 491 nm. Transmission averages above 90 % from 390 to 481 nm, peaking at 93.6 % near 440 nm, providing wide-band throughput across the violet-to-blue window. Past the cut-off, the filter reduces transmission to below 1 % by 505 nm and maintains sub-0.5 % blocking on average from 505 nm to 780 nm – a uniform, deep rejection floor with minimal NIR leakage.
Key Advantages
- Precise 491 nm cut-off – T50 % measured at 491.4 nm with a transition that drops to < 1 % within 14 nm, cleanly separating the blue passband from green and beyond.
- High-throughput passband – Average transmission above 90 % across 390–481 nm with a 93.6 % peak, minimizing signal loss across the full blue channel.
- Broadband blocking – Sub-0.5 % average transmission from 505 nm to 780 nm, providing reliable rejection of green, yellow, red, and NIR wavelengths.
- Hard-oxide durability – Ion-assisted sputtered hard coating withstands heat, humidity, solvents, and frequent cleaning cycles.
- Custom formats – Round, square, or free-form blanks from 5 mm to 450 mm, thickness 0.21–3.8 mm, on Borofloat, soda-lime, Schott D263 T, or Corning Eagle XG substrates.
Typical Applications
- Fluorescence excitation filtering – Cleans up excitation sources for DAPI, CFP, and Pacific Blue fluorophores, passing the full blue excitation band while blocking all emission wavelengths.
- Multi-channel microscopy – Defines a wide blue channel in multi-color imaging systems, preventing cross-talk into green or red channels.
- Laser line clean-up – Removes ASE and broadband background from 473–488 nm laser sources, ensuring spectrally pure illumination.
- Machine vision and inspection – Isolates blue LED or laser illumination in automated inspection systems where green and red ambient light must be rejected.
- Architectural & stage lighting – Delivers a pure sky-blue wash from white or broadband sources with no green or warm-tone contamination.
Need a 500 nm shortpass tailored to your optical path? KUPO Optics provides rapid prototyping and volume production to your exact size, shape, and substrate specifications.
FAQ
B70704 FAQ
What is B70704 and what is it used for?
B70704 is a 470 nm Shortpass Filter. The B70704 sets its 50 % cut-off at 468.5 nm, transmitting the violet and blue spectrum with average throughput exceeding 88 % from 387 to 461 nm and a peak of 91.7 % at 453 nm. Below the cut-off, blocking drops under 1 % by 486 nm and holds below 0.6 % on average through 780 nm. Common uses include Blue-channel machine vision, Fluorescence microscopy, Astronomical imaging, and Color-critical display testing.
What are the key optical specs of B70704?
Key published specs for B70704 include Passband: 419 – 457 nm, 90.1 – 91.7 % T (± 0.8 % ripple); Cut-off (T50): ≈ 469 nm; Edge steepness: ~24 nm (90 → 10 % transition); Blocking: < 0.98 % T above 507 nm (OD ≥ 2); AOI: 0° (normal incidence); custom angles available.
What applications is B70704 best suited for?
B70704 is commonly used for Blue-channel machine vision, Fluorescence microscopy, Astronomical imaging, and Color-critical display testing. Blue-channel machine vision - Defines the blue spectral band for multi-channel inspection, revealing features invisible under broadband white light.
Can B70704 be customized for size, substrate, or coating requirements?
KUPO lists the construction for B70704 as Ion-assisted hard-oxide; 5 – 450 mm shapes, 0.21 – 3.8 mm thick. Published custom options include Edge tuning, ripple smoothing, 45° AOI, rapid prototypes. Custom formats - Round, square, or free-form blanks from 5 mm to 450 mm, thickness 0.21-3.8 mm, on Borofloat, soda-lime, Schott D263 T, or Corning Eagle XG substrates.
What should I know about angle of incidence and durability for B70704?
The published angle of incidence for B70704 is 0° (normal incidence); custom angles available. The hard-oxide coating is built for repeated handling, heat, and cleaning.
