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Laser wavelength
1. Laser wavelength
The wavelength of light refers to the distance a wave travels during one complete oscillation period, typically represented by the Greek letter λ.
The relationship between the wavelength of light,frequency of its electromagnetic vibration, and speed can be expressed by the formula. Speed of light = Frequency × Wavelength (i.e., C = λν). This means that in a same medium, the speed of light remains constant, and frequency and wavelength have an inverse relationship. Therefore, the higher the frequency, the shorter the wavelength, and the greater the energy of a single photon.
The wavelength determines the color of light. According to the human eye's ability to perceive light, light shorter than 380 nm is usually UV light, 380–780 nm is visible light, and longer than 780 nm is IR light.
Different wavelengths of light correspond to different colors: Red light 620~780 nm, orange light 590~620 nm, yellow light 560~590 nm, green light 490~560 nm, cyan light 450~490 nm, blue light 400~450 nm, violet light 380~400 nm.
2. The monochromaticity of lasers
Lasers are the special type of light source. They have purer colors than ordinary light sources and exhibit excellent monochromaticity. For example, the spectrum of an LED light source covers several tens of nanometers, while that of a laser light source is generally only a few nanometers or less (for instance, the spectral width of a single-frequency laser can be less than 1 MHz).
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The spectrum of the green-light LED source | Common laser spectra |
3. Laser wavelength deviation and spectral broadening
Due to the splitting or broadening (energy bands) of the laser's operating energy levels and the constant presence of spontaneous emission, each laser exhibits some degree of deviation in its emission wavelength and spectral broadening.
When specifying the laser wavelength, we usually provide a range. For example, on the datasheet sheet for a 532nm green laser, the wavelength is listed as 532 ± 1 nm, indicating that the laser's actual emission wavelength is between 531~533nm.
Below is the data of two 532 nm lasers measured by an optical fiber spectrometer, and obvious differences can be observed.
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Center wavelength: 531.245 nm | Central wavelength: 532.740 nm |
4. Customized precise wavelength and narrow spectral linewidth
In applications such as sodium guide stars, atomic cooling, coherent measurement, high-resolution Raman spectroscopy, and ultraviolet lithography, precise laser emission wavelengths or extremely narrow spectral linewidths are required. In such cases, users need to clearly specify the laser's central wavelength, acceptable range, and spectral linewidth, as well as related indicators including coherence length, noise, longitudinal mode stability, and side-mode suppression ratio.
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589.159 nm Sodium Guide Star Laser | 670.791 nm Lithium Element Laser |
5. Multi-wavelength lasers and wavelength-tunable lasers
In applications such as genetic testing, flow cytometry, and confocal microscopy, users require systems that multiple wavelengths lasers, and CNI can provide customized services. For details, visit www.cnilaser.net.
CNI also designs and manufactures a series of wavelength-tunable lasers, whose operating wavelength can be adjusted to needs within a certain range. For details, visit www.cnilaser.net.
6. Measurement of light wavelength
For light wavelength measurement, a compact fiber optic spectrometer is common. However, higher-precision central wavelength and narrower spectral linewidth measurements require more expensive spectrum analyzers. For details, visit www.cnilaser.net.
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CNI Fiber Optic Spectrometer | Raman spectroscopy Testing System |
Changchun New Industries Optoelectronics Technology Co., Ltd.
Address: No. 888 Jinhu Road, High-Tech Zone, Changchun, 130103, P.R.China
International Tel:+86-431-85603799
Email: sales@cnilaser.com
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