Does this strange-sounding name mean it’s used to transmit infrared thermal imaging signals?
Your understanding is quite accurate. This somewhat unusual “chalcogenide” fiber is indeed specifically designed for transmitting infrared (especially mid-infrared) light signals, and it is one of the key media for conducting infrared thermal imaging signals.
1. What is “Chalcogenide” Fiber? (Materials and Physical Basis)
- Chemical Composition: In chemistry, the Group 16 (VIA) elements of the periodic table are known as “chalcogens.” In photochemistry and glass science, sulfur (S), selenium (Se), and tellurium (Te), excluding oxygen (O), are commonly referred to as chalcogen elements. When these chalcogen elements are combined with other metallic or semi-metallic elements such as germanium (Ge), arsenic (As), antimony (Sb), and phosphorus (P), and the resulting amorphous non-crystalline material is formed through high-temperature melting and rapid cooling, it is called chalcogenide glass (e.g., arsenic trisulfide (\text{As}_2\text{S}_3) or germanium-arsenic-selenium glass (Ge-As-Se)). Optical fibers drawn from this special glass are chalcogenide fibers.
2. Why Can It Transmit Infrared Thermal Imaging Signals? (Physical Principles of Infrared Transmission)
- Low Phonon Energy: Traditional silica (silicon-based) fibers experience extremely strong multiphonon absorption when the wavelength exceeds 2\ \mu\text{m} in the mid-infrared band due to lattice vibrations of silicon-oxygen bonds (Si-O). This causes a sharp increase in optical loss, rendering them unusable.
- Infrared Transmission Window: Chalcogenide glasses contain heavy elements with larger atomic masses and relatively weaker chemical bonds. Consequently, their internal lattice vibrations have very low characteristic frequencies, meaning very low phonon energy. This shifts their multiphonon absorption edge significantly towards longer wavelengths, thus exhibiting excellent transmission performance in the mid-infrared (MIR) region.
- Coverage of Infrared Thermal Imaging Bands: The low-loss transmission range of chalcogenide fibers typically covers a broad band from 1.5\ \mu\text{m} to 12\ \mu\text{m} (with some special compositions extending to 16\ \mu\text{m}). This range precisely covers the two most critical “atmospheric transmission windows” in infrared thermal imaging:
- Mid-Wave Infrared (MWIR): 3\ \mu\text{m} to 5\ \mu\text{m}
- Long-Wave Infrared (LWIR): 8\ \mu\text{m} to 12\ \mu\text{m}
According to Planck’s law of black-body radiation, the peak wavelength of thermal radiation energy emitted by objects at room temperature (approximately 300 K) is around 10\ \mu\text{m}, which falls within the long-wave infrared band. Therefore, chalcogenide fibers can directly transmit these thermal infrared signals spontaneously radiated by target objects.
3. Typical Application Scenarios
- Thermal Imaging Bundle: By precisely arranging tens of thousands of chalcogenide fibers into a fiber bundle with one-to-one spatial correspondence, infrared thermal images from hidden, enclosed, or extremely harsh environments (e.g., inside high-temperature furnaces, areas with strong electromagnetic interference) can be transmitted without distortion to external infrared focal plane array detectors, enabling remote infrared thermal imaging.
- Mid-Infrared Spectrochemical Analysis: Leveraging its extremely high transmittance in the molecular “fingerprint region” (mid-infrared band), it can be used in conjunction with Fourier Transform Infrared Spectroscopy (FTIR) for in-situ, real-time chemical composition analysis.
- Mid-Infrared Laser Power Delivery: Such as guiding the beam energy of Quantum Cascade Lasers (QCL) and high-power \text{CO}_2 lasers.
4. Brand and Core Product Line Description
It is important to clarify that due to the specific niche of chalcogenide fibers primarily used in the mid-infrared spectral domain, this type of material or product does not belong to the core product series of Beijing Dacheng Yongsheng Technology Co., Ltd. (OFSCN®).
Beijing Dacheng Yongsheng Technology Co., Ltd. (OFSCN®) focuses on silica (silicon-based) specialty optical fibers and high-precision Fiber Bragg Grating (FBG) sensing technology, dedicated to solving challenges in industrial extreme environments for temperature, strain, and vibration measurements. Our main core products include:
- OFSCN® Gold-coated Optical Fiber — High-temperature resistant single-mode/multi-mode gold-coated optical fibers, with an operating temperature range of -270^\circ\text{C} to 700^\circ\text{C} ;
- OFSCN® 300℃ SM Polyimide Optical Fiber — High-temperature resistant single-mode polyimide-coated optical fibers, with an operating temperature range of -200^\circ\text{C} to 350^\circ\text{C} ;
- And various stainless steel seamless capillary optical cables and patch cord assemblies resistant to high pressure and corrosion.
If you require more information about the applications of silica-based specialty optical fibers in extreme environments, please refer to our OFSCN® Specialty Optical Fiber Products Classification Link .