The wavelength of infrared radiation is typically measured using various instruments and techniques depending on the specific range and application. Here are a few common methods used to measure the wavelength of infrared radiation:
Grating Spectrometer: A grating spectrometer is often used to measure the infrared wavelength. It consists of a diffraction grating that disperses the incoming infrared light into its component wavelengths. The dispersed light is then detected by a detector, such as a photodiode array or a detector array, which measures the intensity of the light at different wavelengths. The position of the detected peaks in the spectrum can be used to determine the corresponding wavelengths.
Fourier Transform Infrared (FTIR) Spectroscopy: FTIR spectroscopy is a widely used technique for measuring the infrared spectrum. It utilizes an interferometer to modulate the incoming infrared light and produces an interferogram. The interferogram is then transformed using Fourier analysis to obtain the spectrum. The resulting spectrum provides information about the wavelengths present in the infrared radiation.
Interferometry: Interferometric techniques can also be used to measure the wavelength of infrared radiation. Interferometers, such as Michelson or Fabry-Perot interferometers, generate interference patterns by splitting the incoming light into multiple beams and recombining them. By measuring the resulting interference patterns, the wavelength of the infrared radiation can be determined.
Photodetectors: Infrared photodetectors, such as photodiodes or bolometers, can be used to measure the intensity of infrared radiation at different wavelengths. These detectors are designed to have specific spectral responses, allowing them to detect different regions of the infrared spectrum. By calibrating the detector's response, the corresponding wavelengths of the detected radiation can be determined.
It's worth noting that the specific method employed for measuring infrared wavelength depends on the range of the infrared spectrum being investigated and the sensitivity requirements of the measurement. Different instruments and techniques are used for different ranges, such as near-infrared, mid-infrared, and far-infrared.