Jan 07, 2025
Near Infrared (NIR) light, from 0.8 μm to 1 μm, is invisible to the human eye, meaning you cannot directly identify it with your sight; however, you can detect its presence using specialized cameras or instruments designed to capture NIR wavelengths, which are just beyond the visible red light on the electromagnetic spectrum, and appear as a distinct signal on the device when exposed to NIR sources like sunlight or specific infrared emitters. To "see" near infrared, you need a near-infrared camera or sensor that can detect and translate the NIR wavelengths into a visible image.
SWIR stands for shortwave infrared, which is a range of wavelengths that are not visible to the human eye, from 0.9 μm to 1.7 μm, but sometimes it is classified from 0.7 μm to 2.5 μm . SWIR light is less absorbed and scattered by the atmosphere than visible or MWIR light, allowing for better visibility through haze, fog, and dust.
MWIR stands for midwave infrared, a range of wavelengths in the infrared portion of the electromagnetic spectrum. MWIR cameras typically operate in the 3μm to 5 μm wavelength range, and are used in thermal imaging to capture infrared radiation emitted from objects, and are often used for long-range surveillance applications.
LWIR stands for longwave infrared, a part of the infrared spectrum that detects wavelengths of light that are longer than the human eye can see. LWIR wavelengths typically range from 8 µm to 16 µm. LWIR is also known as thermal imaging, because objects at room temperature emit most of their infrared radiation in this range. Due to this nature, LWIR can be used in the applications like locating people in low visibility, detecting fevers, fire detection etc.
Infrared (IR) refers to a type of electromagnetic radiation with wavelengths longer than visible light but shorter than microwave radiation. It typically falls in the wavelength range of 0.7 to 1000 micrometers (µm), divided into five main categories:NIR(Near-infrared),SWIR(Shortwave Infrared),MWIR(Midwave Infrared),LWIR(Longwave Infrared) and FIR(Far Infrared).
Infrared spectral bands are widely used across industries, including:
Aerospace and Defense: Navigation, target tracking, and thermal surveillance.
Industrial: Quality control, material inspection, and equipment monitoring.
Medical: Thermal diagnostics and imaging.
Environmental: Climate observation, gas detection, and remote sensing.
COQ (Colloidal Quantum Dots): COQ materials are cost-effective and tunable for detecting a broad range of infrared wavelengths, particularly in the shortwave infrared (SWIR) band. They are ideal for applications requiring high sensitivity at a lower cost.
InGaAs (Indium Gallium Arsenide): InGaAs is a high-performance material commonly used in SWIR cameras, providing excellent sensitivity and stability in the 0.9–1.7 µm range. It is widely used in industrial, military, and spectroscopy applications.
COQ-based IR cameras:
Advantages: Lower production cost, tunable detection range.
Disadvantages: May have lower quantum efficiency and thermal stability compared to InGaAs.
Best Suited For: Entry-level applications, such as consumer electronics or low-cost imaging solutions.
InGaAs-based IR cameras:
Advantages: High sensitivity, low noise, and excellent performance in challenging environments.
Disadvantages: Higher cost due to complex manufacturing.
Best Suited For: High-precision applications, including industrial inspection, defense, and scientific research.
T2SL (Type-II Superlattice) detectors detect wavelengths in the 3–5 µm or 3–8 µm midwave infrared (MWIR) range.
Advantages:
High quantum efficiency and reduced dark current.
Customizable bandgap for specific applications.
Greater uniformity and performance compared to traditional MCT (Mercury Cadmium Telluride) detectors.
Applications: Thermal imaging, gas detection, missile tracking, and military-grade target acquisition.
VOx (Vanadium Oxide) detectors operate in the 8–14 µm longwave infrared (LWIR) range, ideal for detecting passive thermal radiation.
Advantages:
High thermal sensitivity for capturing low-temperature differences.
Cost-effective and widely used in uncooled infrared detectors.
Suitable for mass production.
Applications: Security and surveillance, automotive thermal imaging, and non-contact temperature measurements.
Wavelength Band:
InGaAs and CQD: SWIR (0.8–2.5 µm)
T2SL: MWIR (3–8 µm)
VOx: LWIR (8–14 µm)
Performance Needs: High sensitivity (InGaAs, T2SL) vs. cost-effective solutions (CQD, VOx).
Applications: Industrial (InGaAs), low-cost imaging (CQD), military (T2SL), or thermal monitoring (VOx).
