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.
Zinc Selenide (ZnSe) Windows
Zinc Selenide (ZnSe) Windows
Zinc Selenide (ZnSe) is best for use in high power Co2 laser systems due to the high resistance to thermal shock, low absorption coefficient and low dispersion. ZnSe is a relatively soft material with a Knoop Hardness of 120 and is susceptible to scratches and is not recommended for use in harsh environments.
Firebird provides these in several uncoated stock configurations but can provide customized and coated to your specifications.
Zinc Selenide (ZnSe Basics):
ZnSe (Zinc Selenide) windows are optical components made from the compound material Zinc Selenide. They are used as windows, lenses, or beam-splitting elements in infrared (IR) optical systems and laser applications due to their high transmission in the infrared spectrum (especially in the 3-12 micron range). ZnSe is a well-known and widely used material in the field of infrared optics due to its excellent optical properties, such as its high transparency, low absorption, and high thermal stability.
ZnSe windows are made by a crystal growth process, such as Bridgman or Czochralski growth, followed by a polishing process to produce a flat, smooth surface. The surface quality is critical to the performance of ZnSe windows, as surface defects can cause scattering and absorption of light. ZnSe windows are commonly coated with anti-reflection (AR) coatings to improve their transmission and reduce reflections.
ZnSe windows have a relatively high refractive index of 2.4, which makes them suitable for use in a range of optical systems and applications. They have a low absorption coefficient, which makes them ideal for use in high-power laser systems, where the windows need to remain transparent even under high intensity laser light. They also have a high thermal stability, which makes them suitable for use in high temperature environments, such as those encountered in industrial processes or scientific experiments.
One of the main applications of ZnSe windows is in laser beam delivery systems. In these systems, ZnSe windows are used as output windows in laser systems, as they are able to withstand high-power laser light without undergoing any damage or degradation. ZnSe windows are also used in thermal imaging systems, where they are used to transmit the IR light emitted by objects and create an image. They are also used in spectroscopy systems, where they are used to collect and analyze light from molecular vibrations.
ZnSe windows are widely used in a range of IR optical systems and laser applications due to their high transparency, low absorption, and high thermal stability. They are made by a crystal growth process and are typically coated with anti-reflection coatings to improve their performance.
Material Characteristics of ZnSe:
ZnSe (Zinc Selenide) is an optical material with a number of specific characteristics that make it suitable for use in infrared optical systems and laser applications. Some of the key material characteristics of ZnSe include:
High transparency: ZnSe has a high transparency in the infrared spectrum, especially in the 3-12 micron range, making it ideal for use in laser beam delivery systems and thermal imaging systems.
Low absorption: ZnSe has a low absorption coefficient, which means that it does not absorb much of the light that passes through it. This is important for high-power laser systems, where the windows need to remain transparent even under high-intensity laser light.
High thermal stability: ZnSe is highly thermally stable, making it suitable for use in high temperature environments, such as those encountered in industrial processes or scientific experiments.
High refractive index: ZnSe has a relatively high refractive index of 2.4, which makes it suitable for use in a range of optical systems and applications.
Good mechanical properties: ZnSe has good mechanical properties, such as high hardness and toughness, making it suitable for use in applications where the windows may be subject to high stress or impact.
High chemical stability: ZnSe is highly chemically stable, which makes it resistant to corrosion and degradation in harsh environments.
Easy to manufacture: ZnSe is relatively easy to manufacture compared to other IR materials such as Germanium, making it more widely available and cost-effective for use in optical systems.
Advantages of Using ZnSe Windows:
High transparency in the infrared spectrum: ZnSe is highly transparent in the 3-12 micron range, making it ideal for use in laser beam delivery systems and thermal imaging systems.
Low absorption coefficient: ZnSe has a low absorption coefficient, which means that it does not absorb much of the light that passes through it, making it ideal for use in high-power laser systems.
High thermal stability: ZnSe is highly thermally stable, making it suitable for use in high temperature environments, such as those encountered in industrial processes or scientific experiments.
High refractive index: ZnSe has a relatively high refractive index of 2.4, which makes it suitable for use in a range of optical systems and applications.
Good mechanical properties: ZnSe has good mechanical properties, such as high hardness and toughness, making it suitable for use in applications where the windows may be subject to high stress or impact.
High chemical stability: ZnSe is highly chemically stable, which makes it resistant to corrosion and degradation in harsh environments.
Easy to manufacture: ZnSe is relatively easy to manufacture compared to other IR materials such as Germanium, making it more widely available and customizable for use in optical systems.
Drawbacks of ZnSe:
Limited transmission outside of the infrared spectrum: ZnSe is not as transparent in the visible spectrum, making it less suitable for use in optical systems where visible light transmission is required.
High cost: ZnSe can be relatively expensive compared to other optical materials, especially when special coatings are required.
Sensitive to scratches: ZnSe is relatively sensitive to scratches and other surface defects, which can cause scattering and absorption of light. This makes it important to handle ZnSe windows with care to avoid damage.
Limited spectral range: ZnSe has a limited spectral range, with its transparency peaking in the 3-12 micron range. This makes it less suitable for use in optical systems where a broader spectral range is required.Zinc Selenide (ZnSe) Specs:
Wavelength range: 1-14µm | Coating: Uncoated |
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Diameter tolerance: ±0.13mm | Surface Quality: 60/40 |
Thickness tolerance: ±0.13mm | Paralellism: <3 arc minute |
Clear Aperture: 90% | Density: 5.27g/cm3 | Melting point: 1516.85ºC | Young's Modulus: (GPa): 70 | Coefficient of Thermal Expansion: 7.1 x 10-6/°C | Knoop Hardness: 120kg/mm2 |
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