Optical Windows
Optical windows are transparent components made of materials like glass or crystal that are used to protect and control the flow of light in optical systems. IR windows and optics for use in FTIR Spectroscopy and CO2 lasers. This includes discs, rectangular plates and various other geometries.
In various fields, optical windows serve many purposes. They act as protective barriers, shielding sensitive optical components from environmental factors such as dust, moisture, and contaminants. Additionally, they enable the transmission of light while minimizing distortion, reflection, and absorption, thus maintaining the integrity of the optical system.
Optical windows are employed in a wide range of applications, including scientific research, industrial manufacturing, aerospace, defense, and telecommunications. They are utilized in optical instruments like cameras, microscopes, telescopes, lasers, and sensors. By providing a stable optical interface, optical windows facilitate accurate measurements, imaging, and analysis of light, enabling advancements in numerous fields.
Optical windows come in many shapes and sizes but a major factor is their material. The types of materials that an optical window is constructed from dictate the wavelengths (measured in nm) that they can view. In IR It is extremely important that selecting the right material is done to avoid many a headache and a waste of money and time.
If you are having choice fatigue and are getting overwhelmed by all the options please check out our optical window guide.
Silver Bromide (AgBr) Windows
Silver Bromide (AgBr) Windows
Silver bromide (AgBr) optical windows are transparent components made from silver bromide crystals that are commonly used in optical applications, particularly in the IR region. These windows are appreciated for their transparency to infrared radiation, making them suitable for various scientific and industrial applications, including spectroscopy, thermal imaging, and IR sensing.
Silver Bromide’s insolubility and and high transmission range of (0.5 to 35 μm) in the IR region make it especially useful when KRS-5 or KBr are not an option due to toxicity or presence of water. AgBr optical windows find applications in areas such as spectroscopy, FTIR (Fourier-transform infrared) spectroscopy, thermal imaging, gas analysis, and other IR-based technologies. While AgBr is transparent in the infrared, it is opaque in the visible spectrum. This characteristic can be advantageous in certain applications where visible light interference needs to be minimized.
AgBr Windows: Infrared Applications
Silver bromide (AgBr) is a frequently employed orange-hued optical substance for the fabrication of infrared-transmitting windows within gas and liquid sample enclosures employed alongside infrared and FTIR spectrophotometers. a frequently employed orange-hued optical substance for the fabrication of infrared-transmitting windows within gas and liquid sample enclosures employed alongside infrared and FTIR spectrophotometers.
Key Features and Characteristics:
IR Transparency: AgBr windows are transparent in the infrared region of the electromagnetic spectrum, typically from the mid-infrared (mid-IR) to the far-infrared (far-IR) range. This property allows them to be used as optical components in IR spectroscopy and FTIR (Fourier-transform infrared) spectrophotometers.
Chemical Stability: AgBr is chemically stable under normal laboratory conditions. It is not easily corroded or degraded by exposure to common chemicals, making it suitable for use in various sample environments.
High Refractive Index: AgBr has a relatively high refractive index compared to many other optical materials, which can be advantageous for certain optical configurations and applications.
Photosensitivity: One unique characteristic of AgBr is its photosensitivity. It can be sensitive to visible and UV light, causing changes in its properties over time when exposed to these wavelengths. While this property can be a drawback in some applications, it can also be intentionally used in specialized photodetector applications.
Machinability: These windows can be made using hot pressing which can be a more efficient form of production.
Comparisons to Other Materials:
Thallium Bromide (KRS-5): KRS-5 is mainly used in the infrared region as well. While having a higher transmission range than AgBr in the IR regions ranging from 0.6-50µm.
Potassium Bromide (KBr): KBr is commonly used in FTIR spectroscopy and is mostly sought for its excellent transmission range from the UV to the long IR range.
Silver Bromide (AgBr) Specs:
| Wavelength range: 0.5 to 35 μm | Coating: Uncoated |
|---|---|
| Reststrahlen Peak 112.7 μm | Surface Quality: 60/40 |
| Thickness tolerance: ±0.1mm | Reflection Loss 23.9% at 10 μm (2 surfaces) |
| Refractive Index 2.167 at 10 μm (1) (2) | Density: 6.473 g/cc | Melting Point: 432°C | Young's Modulus: 31.97 GPa | Coefficient of Thermal Expansion: 30 x 10-6/°C @ 273 K | Knoop Hardness: Knoop 7 |