Viewport design and manufacture
We design and manufacture custom viewports based on our fusion diagnostic windows. These have been proven for decades in JET to operate under harsh conditions while maintaining minimal optical distortion.
Overview
Our viewports feature a proprietary aluminium interlayer diffusion bonding technique that is used as the joining medium between the optic and its mount. The relatively thick, compliant aluminium joint isolates the delicate optical component from the stresses of manufacture and of subsequent operation at high temperatures. This innovative technology gives our viewports a unique advantage for their combination of high operating temperature, low distortion, low outgassing, and low leak rate.
These advantages have been used by our customers and collaborators in many applications outside fusion, such as space and oil wells based on the high operating temperature, and spectroscopy and atomic traps based on the low leak rate and distortion.

We can combine our diffusion-bonded optics with our vacuum brazing and EB welding processes to design and manufacture fully customisable viewport solutions for nearly any geometry, material, wavelength, and environment.
Our viewport design request form can be used as a guide for any viewport enquiry. Our versatile team is happy to work with any level of detail from a basic sketch to a detailed specification.
Over the years, we’ve curated a collection of viewport designs that share common features and are frequently requested, especially in the field of atom trap research. Utilizing these established designs can lead to substantial cost savings and shorter lead times. We invite you to explore our catalogue page to see if these designs align with your requirements.
Viewports catalogue
Unless otherwise stated, all viewports are guaranteed to a maximum operating temperature of 250C (3C/m ramp rate), and leak rate of <1E-10mBar.L/s
AR coating available, reference price: £3330
Lead time: 4 weeks without AR coating, 12 weeks with AR coating, subject to stock availability.

VPR-100-027
- Flange: 100CF
- Metal: Steel
- Optic: Fused Silica
- Aperture: 73mm
- Price: £7800
Download the VPR-100-027 technical specification (PDF, 0.5MB)

VPR-100-014
- Flange: 100CF
- Metal: Steel
- Optic: Fused Silica
- Aperture: 50mm
- Price: £7200
Download the VPR-100-014 technical specification (PDF, 0.5MB)

VPR-063-014
- Flange: 63CF
- Metal: Steel
- Optic: Fused Silica
- Aperture: 38mm
- Price: £6900
Download the VPR-063-014 technical specification (PDF, 0.5MB)

VPR-100-020
- Flange: 100CF
- Metal: Titanium
- Optic: Fused Silica
- Aperture: 73mm
- Price: £6300
Download the VPR-100-020 technical specification (PDF, 0.5MB)

VPR-100-026
- Flange: 100CF
- Metal: Titanium
- Optic: Fused Silica
- Aperture: 73mm
- Price: £8550
Download the VPR-100-026 technical specification (PDF, 0.5MB)