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Zero-Length Fused Silica Viewports

Zero-Length Fused Silica Viewport

Larson Electronic Glass fused silica viewports are preferred over glass because of their transparency to ultraviolet radiation, higher abrasion resistance, and low coefficient of thermal expansion which makes them very resistant to thermal shock. While fused quartz and fused silica viewports are both silicon dioxide (SiO2), fused silica, which is synthetically grown, is superior to a fused quartz viewport in most regards and does not fluoresce when exposed to UV radiation at 253.7µm as does fused quartz.

NOTE: Maximum bake-out temperature is limited to 200°C due to low temperature braze alloy.

Fused Silica viewports are offered with CF type, and ISO type Quick flanges. Viewport window surfaces offer a minimum of distortion and provide maximum transmission for most applications.


  • Zero-Length offers greater distortion-free view area
  • Nonmagnetic 304 stainless steel to fused silica, brazed seal
  • >90% Transmission from 230nm to 2000nm
  • Optional AR Coatings available
  • CF flanges can be baked to 200°C, 25°C/Min maximum gradient
  • ISO Quick and Large flanges can be baked to 200°C, 25°C/Min maximum thermal gradient

Request a quote on zero length fused silica viewports for your application, or contact Larson Electronic Glass for more information.

Larson Electronic Glass offers "Zero-Length Fused Silica Viewports" available in 6 standard sizes from 3/4 inch through 8 inch with a variety of flange options. Dimensions are in inches unless otherwise noted.

ImageZero-Length Fused Silica ViewportsFlangeView diameter (V)Height (H)Glass thickness (T)Model NumberPart Number
121161-VQZ-075-F1-photo3/4" Zero-Length Fused Silica Viewport1.33" CF.62".35".10"VQZ-075-F1121161
121162-VQZ-150-F2-photo1-1/2" Zero-Length Fused Silica Viewport2.75" CF1.40".50".13"VQZ-150-F2121162
121163-VQZ-150-F3-photo1-1/2" Zero-Length Fused Silica Viewport3.37" CF1.40".62".13"VQZ-150-F3121163
121166-VQZ-150-K5-photo1-1/2" Zero-Length Fused Silica ViewportNW501.40".62".13"VQZ-150-K5121166
121212-VQZ-250-F4-photo2-1/2" Zero-Length Fused Silica Viewport4.5" CF2.69".68".25"VQZ-250-F4121212
121213-VQZ-250-F5-photo2-1/2" Zero-Length Fused Silica Viewport4.62" CF2.69".75".25"VQZ-250-F5121213
121272-VQZ-400-F6-photo4" Zero-Length Fused Silica Viewport6" CF3.88".78".25"VQZ-400-F6121272
121273-VQZ-400-F7-photo4" Zero-Length Fused Silica Viewport6.75" CF3.88".84".25"VQZ-400-F7121273
121292-VQZ-600-F8-photo6" Zero-Length Fused Silica Viewport8"CF5.38".88".37"VQZ-600-F8121292
121302-VQZ-800-F10-photo8" Zero-Length Fused Silica Viewport10" CF7.78".97".37"VQZ-800-F10121302