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Optical Windows and Flats

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G&H deliver high performance optical windows and flats across a wide range of applications in the aerospace and defense, industrial and telecom and life science sectors.

From small precision optical flats for interferometry applications to large optical windows installed in military vehicles, our components are custom designed to deliver performance and value.

Optical windows are a critical component in a variety of applications that require minimal optical impact with maximum mechanical separation between two environments.

Ideally, the window has minimal impact upon the beam transmission properties: does not reflect, absorb, or scatter the beam; does not distort or impact the wavefront; does not bend or deviate the beam path.

The mechanical separation may require thermal, chemical, or environmental tolerance. Careful material selection and coating design are often required to achieve all of the mechanical separation as well as the optical needs.

We design and manufacture our optical windows and flats, by hand, in both the United States and the United Kingdom.

Contact us today to discuss how we can design and manufacture precise optical flats and optical windows for you.


Coating optionsHigh laser damage thresholdBroadband or V-coat anti-reflection
High transmissionDiamond-like coatings for abrasion resistance
Broadband or V-coat anti-reflection
Substrate materialsGe, ZnS, ZnSe, common glasses, fused silica, glass ceramicsGe, ZnS, ZnSe, common glasses, fused silica, glass ceramics
SizesTypical 3-300 mmUp to 450 mm
Especially optimized forHigh energyAbrasive environments
Transmission at high anglesTransmission at high angles
High temperature stabilityHigh long-term stability
Environmental testingHumidity, sea salt spray, DIN, MIL upon requestHumidity, sea salt spray, DIN, MIL upon request
Country of manufactureUSA / UKUSA / UK

G&H Precision Optics Brochure

Download our Precision Optics Products & Solutions Guide

Windows for industrial applications

Optical windows are utilized in lasers, testing chambers, and other systems where the environment on one side may be pressurized, filled with a specific gas, or otherwise need to be chemically separated from the other. The window needs to transmit the photon energy with minimal disruption (highest transmission, lowest absorption and scattering, and minimal polarization or optical path distortion).

Our highest quality optical windows demonstrate very high parallelism, supremely low surface roughness, low transmitted and reflected wavefront errors, and are optically transparent at the operational wavelength range.

The window material is chosen based on environmental factors such as the acidity of the atmosphere, strong vacuums, high pressures, or high temperatures, and the operational wavelength range.

Windows for defense applications

Defense-grade windows from G&H are significantly larger and may be coated with diamond-like coatings to withstand abrasive environments in the desert.

Window thickness is determined by environmental factors: pressure differentials, thermal conditions, and mounting mechanics.


From high transmission broadband anti-reflection coatings to V-coats for high energy applications, our extensive coating capabilities for precision optical components deliver performance across the spectrum from the UV to the FIR. Take a closer look at our optical coatings service.


We have made a significant investment in metrology equipment to ensure that our customers receive quality, high-performing precision optical components. More details on our metrology capabilities can be found on our metrology page.

Environmental testing

Environmental testing of components and coatings is critical for the assurance of performance in rugged conditions. G&H environmental testing capabilities include MIL-C-675C, MIL-C-48497A, MIL-E-12397, and MIL-M-13508C for endurance against abrasion, adhesion, humidity, temperature, and environmental conditions.

Product enquiry

So we can better understand your requirements, please complete the product enquiry form below.