Extreme ultraviolet, 10 to 120 nm
Air and every lens material absorb EUV light, so EUV tools run in vacuum and use mirrors throughout. At 13.5 nm those mirrors are Mo/Si multilayers that peak near 70% reflectance.
- EUV lithography
Photonics across the spectrum, from 13.5 nm to 5 µm
Where each application sits on the wavelength axis, which markets use it, and the optics, lasers and materials behind it. It is also the range I write technical documents for.
λ1550 nmSWIR
Applications, markets and technologies by wavelength
Switch between the three views. Hover or tap a band to light up what sits in it, and select any row for its key wavelengths and the engineering behind it.
Band by band
What each stretch of the spectrum is used for, and what changes in the optics as you move along it.
Deep ultraviolet, 120 to 280 nm
The working sources are excimer lasers and mercury lamps: ArF at 193 nm, KrF at 248 nm and the mercury line at 253.7 nm. Lenses and windows are mostly UV fused silica and CaF₂, chosen for laser durability as much as for transmission.
- DUV lithography
- UV disinfection
- UV curing
Ultraviolet, 280 to 380 nm
UVB and most of UVA. The mercury i-line at 365 nm still prints chips and cures coatings, and the third harmonic of Nd:YAG lands at 355 nm. N-BK7 transmits only from about 350 nm, so UV fused silica takes over below that.
- UV curing
- i-line and g-line lithography
Visible, 380 to 780 nm
Fluorescence lines at 405, 488, 561 and 640 nm, green lasers at 515 and 532 nm, sodium guide stars at 589 nm and the He-Ne metrology line near 633 nm all sit here. Most glasses transmit, so the optics work is mostly color correction and coatings.
- i-line and g-line lithography
- Fluorescence and flow cytometry
- Laser cutting and welding
- Raman spectroscopy
- Laser guide stars
- Interferometry and metrology
- Atomic clocks and quantum sensing
Near infrared, 780 to 1400 nm
Diode lasers at 785, 808, 850 and 905 nm, the rubidium and cesium lines at 780 and 852 nm, and ytterbium fiber lasers near 1070 nm. The O band, 1260 to 1360 nm, carries 1310 nm links over single-mode fiber.
- Laser cutting and welding
- Raman spectroscopy
- Atomic clocks and quantum sensing
- Optical coherence tomography
- Data center links
- SWIR machine vision
- LiDAR
- Fiber-optic telecom bands
Short-wave infrared, 1.4 to 3 µm
Here the cornea and lens absorb the light before it reaches the retina, which is why eye-safe LiDAR and rangefinders work in this band. Erbium amplifiers cover the C and L bands, and thulium and holmium lasers near 2 µm cut tissue through water absorption.
- SWIR machine vision
- LiDAR
- Fiber-optic telecom bands
- Eye-safe laser rangefinding
- Surgical and urology lasers
Mid-wave infrared, 3 to 5 µm
Thermal imagers work here, and CO₂ absorbs at 4.26 µm and CH₄ at 3.31 µm. N-BK7 stops near 2 µm and IR-grade fused silica near 3.5 µm, so the optics move to germanium, ZnSe, sapphire, CaF₂ and chalcogenide glass.
- MWIR thermal imaging
- Gas sensing (NDIR)
Transmission windows of optical materials
Typical transmission ranges for uncoated material, from supplier data. The edges move with thickness and grade, so check the curve for your part before you design near an edge.
- CaF₂130 nm to 10 µm
Excimer optics in the DUV and windows out into the MWIR.
- Sapphire170 nm to 5.5 µm
Hard, scratch-resistant windows from the UV to about 5 µm. Birefringent.
- UV fused silica180 nm to 2 µm
Lenses and windows from the DUV to the NIR.
- IR-grade fused silica250 nm to 3.5 µm
Low-OH silica that reaches 3.5 µm, with less UV transmission.
- N-BK7350 nm to 2 µm
The default glass for visible and NIR optics.
- ZnSe600 nm to 21 µm
MWIR and LWIR lenses and windows.
- Chalcogenide (AMTIR-1)750 nm to 14 µm
Moldable glass for MWIR and LWIR aspheres.
- Germanium1.8 µm to 23 µm
High-index MWIR and LWIR lenses. Opaque a little above 350 K.
Topics within each band
Application notes, selection guides, datasheets, CAD files and circuit design, built from your product data and checked in code.
EUV and DUV
For makers of multilayer mirrors, excimer optics and lithography subsystems: application notes on reflectance and layer tolerances, and datasheets for DUV coatings and CaF₂ optics. EUV Insight is the thin-film tool I built for this band.
UV and visible
For laser, filter and microscope optics makers: selection guides that match filter sets to laser lines, datasheets that state their test conditions, and an AOI shift calculator for your filters.
NIR and SWIR
For diode laser, fiber and LiDAR optics makers: application notes on TEC control and wavelength drift, like my TEC heat-load sample, product pages for telecom and LiDAR filters, and photodiode front-end circuit design.
MWIR
For IR material, lens and QCL makers: transmission and coating datasheets, and lens selection guides for germanium and chalcogenide glass.
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