A wide line-up of light emitters and light sensors to support the development
of mid-infrared measuring instruments
At Hamamatsu Photonics, we believe that photonics technology can provide the means to overcome many of the challenges in areas such as healthcare, energy and the environment.
Our research and development teams are working to develop new photonic devices for environmental applications, specifically in the field of gas analysis in the mid-infrared region.
Gas detection methods and principles
There are two main methods of gas measurement using light: one using ultraviolet, and the other infrared. Gas molecules have unique absorption wavelengths which, in turn, enable gas density to be determined. There are many absorption wavelengths specific to gas that are attributable to the vibration of gas molecules, particularly in the infrared region.
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Unlike other detection methods, infrared optical sensors allow measurement without the sensor making direct contact with the gas, making them suitable for inline and high purity gas measurements, even in remote locations.
There are two types of infrared optical sensors: dispersive and non-dispersive (NDIR). Dispersive measurement separates the irradiated infrared light into constituent wavelengths using a diffraction grating or similar. It can measure various types of gases, but because it requires diffraction grating, the equipment is relatively large. In contrast, non-dispersive measurement does not separate infrared light into wavelength components. In addition, a light source or filter that corresponds to the absorption wavelengths of the relevant gas is required and this excels in gas selectivity. The infrared optical sensor (especially the non-dispersive type) allows gas detection with high performance, high sensitivity, high reliability and long lifetime due to the characteristics of the device.
Images of light source and detector combinations