Uncoated, Thallium Bromoiodide (KRS-5) Window

Description

Shape Optics’ Thallium Bromoiodide (KRS-5) Windows are high-performance optical components designed to provide broad and flat transmission from the near-infrared (NIR) to the far-infrared (FIR) regions. These windows are non-hygroscopic and relatively insoluble in water, making them ideal for a variety of FTIR spectroscopy applications, especially those involving aqueous samples.

Properties and Uses

KRS-5 windows are extensively used in FTIR spectroscopy due to their broad transmission range and high chemical resistance, excluding strong acids. These windows serve as liquid cell windows for the analysis of aqueous samples, protective windows for sensitive optics, and substrates for infrared holographic polarizers. Thallium Bromoiodide’s unique properties also make it suitable for applications where non-hygroscopic materials are required.

General Specifications

• Material: Thallium Bromoiodide (KRS-5)
• Clear Aperture: 85%
• Coating: Uncoated
• Edges: Fine Ground
• Bevel: Protective as needed
• Type: Protective Window

Physical Properties

• Density: 7.37 g/cm³
• Young’s Modulus: 31 GPa
• Coefficient of Thermal Expansion (CTE): 6.0 x 10⁻⁶/°C

Mechanical Properties

• Knoop Hardness: 40.2 kg/mm²
• Poisson’s Ratio: 0.37
• Surface Flatness: λ/10 @ 10.6μm
• Parallelism: < 3 arcmin

Chemical Properties

Thallium Bromoiodide (KRS-5) is non-hygroscopic and relatively insoluble in water, which makes it suitable for use in FTIR spectroscopy with aqueous samples. However, it has limited resistance to strong acids and requires careful handling due to its toxicity. It can be absorbed through the skin, so gloves must be worn while handling these windows.

Optical Properties

• Index of Refraction: Varies with wavelength
  • 2.45 @ 1μm
  • 2.38 @ 4μm
  • 2.37 @ 10μm
  • 2.21 @ 40μm
• Surface Quality: 60-40 scratch-dig

Transmission Wavelength Range

KRS-5 windows provide an extensive transmission range from 700 nm to 40,000 nm. This broad range covers both the NIR and FIR spectra, making these windows highly versatile for various optical applications. Their flat transmission characteristics ensure consistent performance across the entire spectral range.

Conclusion

Shape Optics’ Thallium Bromoiodide (KRS-5) Windows are engineered to deliver superior optical performance across a wide spectral range, making them ideal for FTIR spectroscopy and other advanced optical applications. Their broad transmission, non-hygroscopic nature, and chemical resistance make them valuable components in many optical systems. Proper handling and storage are crucial due to their toxicity and sensitivity to strong acids.