Ideal Vacuum Cube Viewing Window Plate Assembly for 6x6 Vacuum Chamber 3/8" Fused Quartz

This Ideal Vacuum Cube 6x6 inch vacuum chamber fused quartz viewing window plate assembly is designed to fit our 6x6x6 or 6x6x12 modular Cube chambers.

The fused quartz window viewing plate assembly is often selected for experiments where improved optical clarity, extended wavelength transmissivity is required beyond the visible range, and where cost is a factor.

Our fused quartz windows are manufactured with the highest quality natural quartz resulting in the highest levels of purity and lowest inclusion and bubble levels. Comparable to Heraeus TSC-3, these windows have improved transmittance, and a wider useful wavelength range than standard glass. Characteristics include low refractive index variations and low thermal expansion coefficient. Fused quartz is used for semiconductor applications such as plasma etch and deposition systems and recommended when low alkali and low aluminum content are specified. It is often used for transmissive optics in the visible and near-to-mid infrared wavelengths where a high laser damage threshold is required. Fused quartz has absorbtion bands in the 2600 to 2900 nm region, similar to fused silica but not as strong. It is unsuitable for UV work due to absorbtion in the 270 nm region.

Note that fused quartz stock is limited as Ideal Vacuum is transitioning to fused silica as its premium window offering. Also note that fused quartz windows may be erroneously labeled with fused silica part numbers. You may verify your window material by checking your sales invoice.

We also offer Cube window plate assemblies and replacement window panes with standard low-iron tempered glass or fused silica. Tempered glass is commonly used for general, direct observation of roughing or high-vacuum chamber processes and can be used to facilitate optical alignments of chamber components, observe degassing of fluids, or used to help teach in-vacuo processes by direct observation. The glass material is standard low-iron float glass. Surface quality and flatness is Q4 per ASTM 1036-06 and 1048-04. The low iron content of the glass results in it having a slight blueish tint. This economical glass is unsuitable for laser experiments below visible or beyond near-infrared (NIR) wavelengths.

Our high purity fused silica replacement windows are ground and polished to optical grade on both sides with a total thickness variation (TTV) of <10µm, a surface finish of S/D 40/20, and a surface roughness of Ra < 1 nm. These windows have appreciably improved transmittance, and a wider useful wavelength range than standard glass. Characteristics include extraordinarily low refractive index variations, low birefringence values, and an ultra-low thermal expansion coefficient. Fused silica is used for transmissive optics where a high laser damage threshold is required. Fused silica is used for optics operating in the deep UV, visible, and the near infrared wavelength range.


Our Cube viewing windows employ an innovative, zero metal-to-glass contact design that holds the 3/8” thick window pane to an aluminum mounting plate. This cushioned window mounting system ensures operator safety and is less prone to leakage than other viewport window configurations, even at high vacuum pressures. Ideal Vacuum Cube windows are delivered fully assembled and use Viton O-rings and Teflon spacers. Bakeout temperatures to 150 °C are permissible.

The viewing window plate assembly is interchangeable with other Cube plates and can be added to an Ideal Vacuum Cube system anytime. The viewing window can be implemented as a fixed side, or a door (with our optional hinge assembly and hardware kit, P106868) on the Cube chamber.

The viewing window plate assembly, like all our other Cube plates, is built with our patented Taper-Seal technology which incorporates sloped sealing features to help prevent damage to the vacuum sealing surfaces. All Ideal Vacuum Cube plates are CNC milled from a single block of lightweight 6061-T6 Aluminum Alloy.

Before it ships, every viewing window plate assembly is visually inspected for window media imperfections, helium leak tested, cleaned and sealed, ensuring that it operates correctly, safely, and is ready for immediate installation upon delivery.

NOTE: All viewing windows or viewports are inherently fragile, should be handled carefully, and always inspected before use. Ideal Vacuum viewing windows are designed and rated for VACUUM ONLY and can be susceptible to thermal shock if exposed to rapid temperature changes (>10° C /min). If directing a laser beam through the window, make sure the laser’s wavelength can be reasonably transmitted through the window’s material. Please download and read all the safety warnings in the IVP Cube Viewing Window Assembly Manual.