Germanium Optics

Germanium (Ge) is a high-refractive-index material well-suited for manufacturing infrared optical (EO/IR) lenses, windows, and mirrors.

Lattice Materials is a world leader in manufacturing highly complex germanium optics in prototype or production quantities.

We specialize in the custom growth of Czochralski (Cz) crystals in hard-to-find sizes or unique orientations, with custom electrical resistivity and special optical transmissions.

There are several technical challenges in manufacturing germanium components for infrared optical systems, such as maintaining high optical quality over a wide range of temperatures, minimizing unwanted radial resistivity gradients, and reducing the absorption of infrared radiation.

Rely on our talented crystal growth technicians to overcome these challenges and deliver demanding specifications.

Optical Precision

Optical precision is critical to meet specific requirements related to accuracy, surface quality, and overall optical performance.

Our ISO 9001:2015 Quality Management certification enables us to ensure your infrared optical lens meets or exceeds your expectations.

We fabricate germanium components, including optical lenses, prisms, and optical filters, with extremely high precision, ensuring exceptional performance in a wide range of infrared optical applications.

  1. Creating a single crystal of germanium is the starting point for manufacturing high-quality components. The crystal structure and defect density can significantly affect its optical and electrical properties. By growing a single crystal, we produce components with a consistent crystal structure and high purity.
  2. Next, the crystal is processed into the desired shape using precision cutting, grinding, and machining techniques to achieve the precise flatness or curvature required.

Crystal Structure: Diamond cubic

Density, g/cm3: 5.323

Mohs Hardness: 6.3

Index of Refraction @25℃: @3 microns, n = 4.0045

Absorption Coefficient @25℃, cm-1 @3 microns, a = 0.0047

Picture-Perfect Finishing

Achieving the perfect finish on germanium components requires expertise, experience, specialized equipment, and quality control techniques.

  • Grinding and polishing: The initial shaping of the germanium substrate using precision grinding and polishing is critical for a smooth and uniform surface. A series of steps are followed, each with increasingly finer abrasives, until we achieve the desired surface finish.
  • Coatings: Specialized anti-reflective coatings and treatments can further enhance the performance of germanium optics by reducing reflection and absorption, improving transmission, and increasing durability.
  • Specialized measurement and inspection: Using specialized measurement tools and inspection equipment, we ensure that the surface roughness, curvature, and other critical parameters meet strict tolerances and quality standards.
  • Careful handling and cleaning: Germanium optics are extremely hard and brittle. Proper cleaning and packaging procedures minimize any damage or contamination that could affect its optical performance.
  • At Lattice Materials, we have an as-built Class 10,000 cleanroom to clean and package polished parts.

The end goal is to produce germanium optics that meet or exceed the demanding requirements of various applications, from infrared thermal imaging and sensing to spectroscopy and laser systems.

Atomic Density, atoms/cm3: 4.416 

Lattice Constant, nm @23℃: 0.565754

Surface Tension mN/m (=dyne/cm): 650
Poisson’s Ratio 125K-375K: 0.278

Melting Point℃: 937.4

Do you have a custom requirement for germanium optical components?

Send us your specific requirements, and our technical sales representatives will analyze what is needed to deliver ready-to-use components within your lead time.

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