Optical Windows: Glass, Germanium, ZnSe and Medical Laser

Optical windows are flat, transparent plates that pass light into or out of a system with minimal distortion, scattering or absorption, while sealing off the optical path from dust, spatter, gas or a different physical environment. Wavelength Opto-Electronic designs and manufactures windows across a range of wavelengths, coatings and materials. These include fused silica, N-BK7, sapphire, germanium and zinc selenide. The range also covers ZnSe Brewster windows and thin film polarizers for CO2 beam lines. Whether you’re protecting the focusing optics in a fiber laser cutting head or replacing a worn window in a medical laser handpiece, the catalogue gives you a starting point, and custom builds cover the rest.

Window types and materials

Glass optical windows (WFS and WBK series). Fused silica and BK7 windows cover the ultraviolet through visible and into the near-infrared. Fused silica offers a low coefficient of thermal expansion, high transmittance and low scattering. BK7 is the cost-effective choice where its transmission range is sufficient. Coated fused silica windows are widely used as protective windows in fiber laser cutting and welding systems, with single- and dual-wavelength AR coating options.

IR optical windows (WGE series). Germanium windows isolate different physical environments while transmitting infrared light. Use them where a visible-range glass would block the band you need, for example in thermal sensing or IR laser paths.

Medical laser windows (WBK series). These windows are built for CO2, Q-switched Nd:YAG, Er:YAG, Ruby and Alexandrite laser systems. They have been used as replacement optics in systems from manufacturers including Con-Bio, ESC, Sharplan, Candela and Coherent. The catalogue lists dual-wavelength variants that pair a treatment wavelength with a visible aiming beam.

ZnSe optical windows (WZ series) and ZnSe Brewster windows (WZB series). Zinc selenide is the standard material for high-power CO2 laser systems and other thermally demanding applications. Windows are available coated or uncoated and in a wide variety of shapes and sizes. Brewster windows are set at Brewster’s angle to minimize reflection loss for p-polarized light without an AR coating.

ZnSe thin film polarizers (TFP series). A coated ZnSe plate oriented at Brewster’s angle splits a CO2 laser beam into its S- and P-polarized components, or combines two beams of opposite polarization. The thin-film coating raises s-polarized reflectivity while keeping p-polarized transmission high.

Applications

Optical windows show up wherever a laser or imaging path has to cross a boundary:

• Laser materials processing: protective windows for fiber laser cutting, welding, drilling, engraving and cleaning heads, and for galvo-based laser scanning and 3D dynamic scanning systems.
• Additive manufacturing: beam-entry and protective windows in metal powder-bed and other laser-based 3D printing systems.
• Solar and electronics: scribing and grooving of solar panels.
• Medical and aesthetic lasers: replacement windows for CO2, Nd:YAG, Er:YAG, Ruby and Alexandrite treatment systems.
• High-power CO2 systems: ZnSe windows, Brewster windows and thin film polarizers for beam delivery and polarization control.

The full spec table on this page lists wavelength, material, diameter or dimension, thickness, angle of incidence and application for every part number. You can filter by the wavelength your source emits or by the system you’re servicing.

Why buy through Wavelength Optics USA

Wavelength Optics is the US arm of Wavelength Opto-Electronic. You work with a local team in your time zone instead of routing questions overseas.

• Fast quoting. Send part numbers or a drawing and we’ll turn around a quote. Lead times and coating options are confirmed per request.
• Selection support. If you’re unsure whether fused silica, sapphire or ZnSe fits your wavelength and power level, or whether you need a Brewster window instead of an AR-coated one, our engineers can talk it through with you.
• Custom builds. Non-catalogue diameters, thicknesses, shapes, coatings and materials are available. Submit your specifications through the RFQ form and we’ll coordinate directly with the manufacturing team.
• Replacement sourcing. For medical and industrial laser maintenance, we can help match an existing window to a catalogue part or a custom equivalent.