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Infrared Transparent Materials

An Essential Resource for Understanding Optical Material Behavior Across IR Wavelengths.

The Reality of IR Transparency

A frequent misunderstanding in the field of thermal imaging is the belief that materials which appear clear or see-through under visible light will demonstrate identical transparency when examined under infrared wavelengths. This represents a significant error in understanding. Crystalline structures that exhibit complete transparency in the visible spectrum frequently become entirely opaque when evaluated across infrared frequency ranges. Below you will find a detailed reference list of standard optical materials employed in lens fabrication and window applications, including their specific transmission capabilities within the infrared domain.

Optical Materials Reference Library

Amtir-1 Glass
Ge₃₃As₁₂Se₅₅
Transmission: 0.8-13 microns

A specialized chalcogenide glass blend delivering wide-range infrared transmission capabilities, frequently employed in thermal detection systems and IR optical configurations that demand mid-wavelength spectrum performance.

Barium Fluoride
BaF₂
Transmission: 0.15-12.5 microns

A superior optical substrate delivering outstanding transmission spanning from deep ultraviolet wavelengths through the mid-infrared spectrum, perfectly suited for spectroscopic analysis and multi-band imaging platforms.

Potassium Bromide
KBr
Transmission: 0.21-28 microns

Extensively employed in Fourier Transform Infrared spectroscopy equipment, providing impressive IR spectrum coverage. Moisture-absorbing characteristics demand strict environmental monitoring and protective measures during use.

Caesium Iodide
CsI
Transmission: 0.25-55 microns

Delivers the most extensive infrared transmission spectrum among commonly available substrates, reaching deep into far-infrared territory. Intensely hygroscopic and demands specialized protective coatings for field deployment.

Potassium Chloride
KCl
Transmission: 0.21-21 microns

An economical substrate choice for infrared observation windows and spectroscopic instrumentation. Sensitive to moisture absorption necessitating regulated atmospheric conditions for optimal function.

Cadmium Telluride
CdTe
Transmission: 2-25 microns

A semiconductor substrate delivering remarkable transmission across mid to far-infrared bands, frequently utilized in carbon dioxide laser apparatus and thermal detection equipment.

Sapphire
Al₂O₃
Transmission: 0.17-5.0 microns

Remarkably robust crystalline substrate featuring excellent mechanical hardness and chemical inertness. Preferred choice for protective observation ports in demanding industrial operating conditions.

Silicon
Si
Transmission: 1.2-10, 50-100 microns

Standard semiconductor quality silicon delivering reliable infrared transmission properties. Blocks visible spectrum light while permitting passage of near and mid-infrared radiation.

High Resistivity Silicon
Si (HR)
Transmission: 1.2-10, 50-100 microns

Elevated purity silicon featuring minimized absorption characteristics, delivering enhanced capabilities for infrared optical elements and thermal detection filter implementations.

Calcium Fluoride
CaF₂
Transmission: 0.15-9.0 microns

Minimal absorption optical substrate featuring outstanding transmission spanning UV to mid-infrared bands. Regularly specified in high-grade lens assemblies and precision optical instrumentation.

Gallium Arsenide
GaAs
Transmission: 1-15 microns

Semiconductor composition featuring extensive mid-infrared transmission. Regularly deployed in high-output CO₂ laser equipment and thermal imaging optical frameworks.

Sodium Chloride
NaCl
Transmission: 0.2-20 microns

Economical infrared window substrate frequently deployed in laboratory spectroscopic work. Intense hygroscopic behavior demands meticulous storage protocols and handling practices.

Germanium
Ge
Transmission: 2-17 microns

High-quality infrared optical substrate featuring elevated refractive index, broadly deployed in thermal detection lenses and forward-looking infrared platforms. Temperature-sensitive optical characteristics merit careful evaluation.

BK7 Schott Glass
BK7
Transmission: 0.35-2.0 microns

Benchmark optical glass for visible and near-infrared implementations. Superior optical uniformity establishes it as the go-to selection for precision optical elements.

Fused Silica UV Grade
SiO₂
Transmission: 0.18-3.5 microns

Ultra-high purity synthetic silica featuring remarkable UV transmission performance. Minimal thermal expansion coefficient renders it perfect for precision optics and laser apparatus.

Fused Silica IR Grade
SiO₂
Transmission: 0.18-3.5 microns

Engineered specifically for near-infrared uses with amplified transmission attributes. Provides exceptional thermal constancy and optical effectiveness in challenging operational settings.

Lithium Fluoride (VUV)
LiF
Transmission: 0.12-6.5 microns

Dedicated vacuum UV quality substrate extending transmission into extreme ultraviolet wavelength zones. Critical for VUV spectroscopic analysis and far UV optical implementations.

Magnesium Fluoride
MgF₂
Transmission: 0.13-7.0 microns

Birefringent crystal structure offering broad spectral transmission. Regularly employed as foundation for optical thin films and UV-visible-NIR optical elements.

Quartz
SiO₂
Transmission: 0.15-3.3 microns

Natural crystal silica featuring reliable UV and near-infrared transmission. Delivers outstanding thermal and chemical durability for optical window implementations.

Thallium Bromoiodide
KRS-5 (TlBr-TlI)
Transmission: 0.6-40 microns

Remarkably broad infrared transmission substrate reaching into far-infrared wavelengths. Hazardous composition necessitates cautious handling protocols; favored in specialized spectroscopic uses.

Zinc Selenide (CVD)
ZnSe
Transmission: 0.55-20 microns

High-grade laser substrate manufactured through chemical vapor deposition methods. Industry benchmark for carbon dioxide laser optics and advanced thermal detection platforms.

Zinc Sulfide Cleartran
ZnS
Transmission: 0.37-14 microns

Multi-band optical substrate featuring visible to mid-infrared transmission. Outstanding mechanical toughness makes it appropriate for protective observation port implementations.

Infrared Plastic
Polymer
Transmission: 8-12 and 15-40 microns

Purpose-designed polymer composition transparent across long-wave and far-infrared bands. Lightweight, budget-conscious substitute for targeted thermal detection implementations.

Infrared Wavelength Band Categories

Near-Infrared (NIR) 0.9-1.7μm

The near-infrared frequency region spans 0.9 to 1.7 microns and has proven its effectiveness throughout research facilities, protective installations, monitoring systems, defense deployments, and various industrial implementations. Featuring diverse capabilities across numerous industry sectors, near-infrared detection technology has achieved increasing worldwide acceptance and implementation.

Short-Wave Infrared (SWIR) 2-6μm

The short-wave infrared region is distinguished by numerous research implementations, spanning a wavelength range from 2 to 6 microns. At this time, ITI does not fabricate short-wave infrared imaging equipment; nevertheless, we maintain the technical knowledge and design proficiency to engineer customized short-wave detection solutions matched to your particular operational demands and implementation specifications.

Mid-Wave Infrared (MWIR) 3-5μm

The mid-wave infrared wavelength band encompasses 3 to 5 microns of the electromagnetic radiation spectrum. This frequency range delivers superior atmospheric penetration and proves especially capable for identifying temperature variations in ambient to moderately heated temperature zones, rendering it beneficial for focused thermal detection uses.

Long-Wave Infrared (LWIR) 7-14μm

Without question, the long-wave infrared region constitutes the most widely commercialized and desired infrared imaging technology available today. Long-wave infrared covers 7 or 8 to 14 microns, delivering the most extensive spectral range among existing imaging platforms. Importantly, essentially all substances present in nature emit thermal energy within this wavelength region, thus positioning it as an extremely adaptable imaging solution with wide-ranging application potential and comprehensive general-purpose functionality spanning countless disciplines.

Disclaimer: Although we endeavor to ensure 100% precision in our reference documentation and digital tools, we are unable to offer complete guarantees concerning information accuracy. This resource should be employed as a rapid reference aid exclusively. For mission-critical implementations, kindly verify technical specifications with substrate producers or perform independent validation testing to confirm appropriateness for your particular use case.