What is Chalcogenide Glass Material

Chalcogenide glass materials are unique optical materials composed of elements from Group 16 of the periodic table, specifically sulfur, selenium, and tellurium, often combined with other elements like germanium and arsenic. These glasses are prized for their exceptional infrared (IR) transmission capabilities and thermal stability, making them ideal for various advanced optical applications.

chalcogenide glass Optics 3

Properties and Uses

Chalcogenide glasses are extensively used in infrared optics due to their ability to transmit light across a wide IR spectrum. These materials are essential for thermal imaging, IR spectroscopy, and laser systems. Their low phonon energy minimizes absorption losses, which is crucial for high-performance IR applications. Additionally, chalcogenide glasses exhibit remarkable chemical durability and thermal stability, making them suitable for use in harsh environments.

General Specifications

  • Composition: Varies by type (e.g., Ge33_{33}33​As12_{12}12​Se55_{55}55​, Ge28_{28}28​Sb12_{12}12​Se60_{60}60​)
  • Density: Ranges from 3.20 to 4.66 g/cm³
  • Thermal Expansion: 12.5 to 22.5 x 10⁻⁶/°C
  • Transition Temperature: 185°C to 368°C
  • Refractive Index: Varies with wavelength and type (e.g., 2.5971 to 2.9316 at 1 μm)
GradeCompositionDensity (g/cm³)

Specifications for Chalcogenide Lens Manufacturing

Diameter1-25 mm1-25 mm
Diameter Tolerance±0.015 mm±0.005 mm
Thickness Tolerance0.03 mm0.005 mm
Irregularity (P-V)<1 μm<0.6 μm
Irregularity (RMS)0.3 μm0.08 – 0.15 μm
Centering Error1′1′
Surface Quality60-4020-10

Material Properties of Chalcogenide Glass

Sr. No.GlassIRG 22IRG 24IRG 25IRG 26IRG 27
2Density4.41 g/cm³4.47 g/cm³4.66 g/cm³4.63 g/cm³3.20 g/cm³
3Thermal Expansion (20-100 °C)12.5 × 10−6^{-6}−6/K20.0 × 10−6^{-6}−6/K14.0 × 10−6^{-6}−6/K21.4 × 10−6^{-6}−6/K22.5 × 10−6^{-6}−6/K
4Transition Temperature368 °C225 °C285 °C185 °C197 °C
5Thermal Change dN/dT94.8 × 10−6^{-6}−6/K (1 μm)46.0 × 10−6^{-6}−6/K (1 μm)79.2 × 10−6^{-6}−6/K (1 μm)76.2 × 10−6^{-6}−6/K (1 μm)15.6 × 10−6^{-6}−6/K (1 μm)
67.7 × 10−6^{-6}−6/K (5 μm)21.1 × 10−6^{-6}−6/K (5 μm)62.0 × 10−6^{-6}−6/K (5 μm)33.4 × 10−6^{-6}−6/K (5 μm)-3.2 × 10−6^{-6}−6/K (5 μm)
67.1 × 10−6^{-6}−6/K (10 μm)20.3 × 10−6^{-6}−6/K (10 μm)61.1 × 10−6^{-6}−6/K (10.6 μm)32.2 × 10−6^{-6}−6/K (10.6 μm)-3.7 × 10−6^{-6}−6/K (10.6 μm)
6Refractive Index2.5971 (1 μm)2.7249 (1 μm)2.7284 (1 μm)2.9316 (1 μm)2.4841 (1 μm)
2### Molded Chalcogenide Aspheres for Infrared Optics

Physical Properties

Chalcogenide glasses typically have a higher density compared to traditional optical glasses, contributing to their robustness and durability. Their thermal expansion coefficients are moderate, ensuring compatibility with various substrates and reducing thermal stress. The transition temperatures of chalcogenide glasses are relatively high, indicating good thermal stability and suitability for high-temperature applications.

chalcogenide Material

Mechanical Properties

Chalcogenide glasses have moderate hardness, generally lower than conventional glasses, making them easier to process and mold. However, this also makes them more susceptible to scratching. The Knoop hardness varies among different types, allowing selection based on specific application requirements.

Chemical Properties

Chalcogenide glasses are chemically stable and resistant to water and most acids, ensuring durability in various environmental conditions. This chemical resistance makes them suitable for use in applications where exposure to harsh chemicals is expected. The unique composition of chalcogenide glasses ensures minimal reaction with environmental elements, enhancing their longevity.

Optical Properties

Chalcogenide glasses offer excellent infrared transmission, covering wavelengths from 1 to 16 μm. Their high refractive indices are beneficial for designing high-performance IR optics. The refractive index varies slightly with composition and wavelength, providing flexibility in optical design to meet specific application needs.

Transmission Wavelength

The broad transmission range of chalcogenide glasses, from 1 μm to 16 μm, makes them suitable for various IR applications, including defense, medical imaging, and environmental monitoring. This wide range ensures versatility and high performance across multiple wavelengths, making chalcogenide glasses an essential component in advanced infrared optical systems.

chalcogenide Glass spectrum

Shape Optics’ chalcogenide glass materials are engineered to deliver exceptional performance in infrared optical systems. Their broad transmission range, excellent thermal stability, and chemical durability make them ideal for advanced IR applications. By leveraging the unique properties of chalcogenide glasses, Shape Optics provides solutions that meet the demanding requirements of modern infrared technology.


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