How zygo delivers high-performance optics from an unmatched range of substrates

Justin E. Turner, Division Vice-President (Optics), Zygo

To make sure high-performance optical systems don't crack under pressure, selecting the right material is not a secondary consideration, it is foundational. The substrate used for an optical window or mirror governs the system's optical performance, thermal stability, and resilience under operational conditions. Zygo™, a global leader in precision optics, distinguishes itself through a material-agnostic capability, manufacturing from an exceptionally wide range of optical (and non-traditional) materials to ensure optimal performance for any application.

While many optical manufacturers routinely work with standard materials like BK7, fused silica, and a variety of flint glasses (useful for general-purpose visible-spectrum optics) Zygo goes far beyond the conventional. The company is as comfortable working with these everyday materials as it is with complex, specialty crystal and ceramic substrates that most other suppliers avoid. This capability is a core differentiator and a critical asset for customers requiring custom, high-performance solutions.

Zygo's capabilities span commonly used materials and those that demand specialized knowledge and infrastructure. Materials such as germanium, nickel-plated aluminum, single- and polycrystalline silicon, sapphire, and zero-expansion ceramics like ZERODUR® and CLEARCERAM®-Z are all routinely handled at Zygo. Each of these materials serves a distinct purpose.

INFRARED MATERIALS

Germanium (Ge) is valued for its transparency in the infrared spectrum, making it ideal for IR optics and thermal imaging systems. Nickel-plated aluminum is typically used as a substrate for mirrors due to its machinability and reflective coating compatibility. Silicon, depending on whether it is single- or polycrystalline, is another material with dual utility. It can serve both transmissive and reflective roles, especially in telecom or high-heat applications, due to its transparency at certain IR wavelengths and excellent thermal conductivity.

Zinc selenide (ZnSe), recognized by its yellow hue, is another material used primarily in the infrared range. Like ZnS and ClearTran®, ZnSe is essential in thermal imaging systems, and Zygo has developed processes to handle its particular sensitivities.

ZERODUR® AND CLEARCERAM®

In semiconductor manufacturing, where tolerances are measured in nanometers and even picometers, Zygo supplies precision optics and mirrors made from materials like ZERODUR® and CLEARCERAM®-Z. These materials offer an ultra-low coefficient of thermal expansion (CTE), close to zero parts per million, meaning that even under thermal fluctuation, they retain their dimensional integrity. This makes them ideal for use in wafer stages and metrology frames for inspection and lithographic systems, where even a half-nanometer of distortion can be catastrophic to process yield.

MULTISPECTRAL ZINC SULFIDE (ZNS) AND CLEARTRAN®

Zygo also works with more technically demanding materials that are essential in aerospace, defense, and advanced scientific applications. Multispectral zinc sulfide (ZnS) and ClearTran® are standout examples. These materials transmit across both the visible and infrared spectra, enabling systems with multiple sensors to operate behind a single optical window (also referred to as common aperture or shared aperture). Their use is common in aerospace, where using a shared aperture can help designers achieve the weight portion of their SWaP budget (Size, weight, and power) for manned or unmanned reconnaissance pods.

CALCIUM FLUORIDE, MAGNESIUM FLUORIDE, AND BARIUM FLUORIDE

Calcium fluoride (CaF₂), magnesium fluoride (MgF₂), and barium fluoride (BaF₂) are crystalline materials known for their transmission from vacuum ultraviolet to infrared. These are extremely difficult to process (prone to damage from thermal and mechanical shock), and physically soft, but they are irreplaceable in applications requiring full-spectrum optical transparency. Zygo's experience with these fragile materials, including their use in airborne environments, speaks to its advanced polishing and material handling protocols.

SAPPHIRE

Despite this, its robustness makes it ideal for aircraft windows, sensor domes, and other exposed optical systems in hostile environments.

CORDIERITE

Beyond these, Zygo handles advanced ceramics and hybrid materials that extend its capabilities into truly specialized applications. Cordierite is one such material, a ceramic that can be engineered to match the coefficient of thermal expansion of system-critical components like titanium or ZERODUR®. Because Cordierite starts as a powder that is formed into molds and then fired, it allows for complex shapes and lightweight structures that would be difficult or impossible to achieve using traditional glasses or crystals. This makes it an invaluable choice in opto-mechanical systems requiring thermal compatibility and structural complexity.

SPINEL AND ALON

Zygo also fabricates optics from Spinel and ALON (aluminum oxynitride), ultra-hard transparent ceramics used primarily in defense applications and specifically for conformal windows. These materials are designed to withstand ballistic impacts and explosive forces while maintaining optical clarity. Their hardness rivals sapphire (although they have optical transmission limitations), and their resistance to environmental stress makes them suitable for armored vehicle windows and protective sensor housings. Again, these materials are exceptionally hard to process, but Zygo's experience and polishing expertise ensure reliable performance.

SILICON & SILICON CARBIDE

Silicon carbide (SiC) has garnered recent interest in the defense and aerospace industry for its unique mechanical properties. Lightweight, extremely stiff, and highly thermally conductive, silicon carbide is an ideal material for spaceborne optics and mirror systems. Its composite nature allows for low-mass, high-rigidity structures that survive launch stresses and perform reliably in orbit. It behaves much like carbon fiber-rigid and lightweight-but in a fully ceramic form. Zygo's ability to process and finish this material gives it a strong presence in aerospace and satellite optics.

Closely related in versatility is silicon, available in both single- and polycrystalline forms. Like silicon carbide, it offers excellent thermal conductivity and is well-suited for high-heat environments. Silicon also has the unique optical advantage of partial infrared transparency, making it a preferred material for telecom applications as well as infrared mirrors and windows. Zygo's proficiency in processing both silicon and silicon carbide allows it to meet the precise thermal and optical needs of advanced aerospace, defense, and telecommunications systems.

MATERIAL PHILOSOPHY

substrates, from IR-transparent semiconductors to tailored ceramics, Zygo provides its customers with unmatched freedom to design optical systems without material constraints.

This philosophy, combined with deep manufacturing expertise, advanced metrology, and cleanroom-level quality control, allows Zygo to deliver precision optics for sectors where performance, not compromise, is the priority. Aerospace, defense, semiconductors, telecommunications, and scientific research all rely on Zygo to produce optics that are not just dimensionally accurate, but thermally, mechanically, and optically engineered for the environments they will face.

SUMMARY

In industry sectors where precision is non-negotiable, Zygo's material flexibility is more than an offering, it's a strategic advantage. Whether it's a salt crystal for UV-to-IR transmission, a bullet-resistant ceramic for a military vehicle, or a zero-CTE mirror for photolithography, Zygo delivers.

The result is an optical partner that customers return to time and again, not because it's convenient, but because it's the only choice when performance truly matters.

ENDS