Boutique Express | Narrow Linewidth Laser

Since the invention of the Laser, with its excellent characteristics, it has been widely used in industrial processing, medical beauty, scientific research and other fields. Laser has four main characteristics, namely high brightness, good directionality, good monochromaticity, and high coherence. These properties are related to each other, making the laser suitable for different scenarios.

Changchun New Industries independently develops and produces a variety of lasers with "monochromaticity" tending to the extreme - narrow linewidth lasers, which have been widely used in DNA sequencing, flow cytometry, digital imaging, analytical chemistry, particle measurement, lasers in recent years Confocal microscopy, Raman spectroscopy, etc.

CNI laser
What is "narrow line width"?
The spectral line width (FWHM - Full Width Half Maximun) refers to the frequency range corresponding to when the light intensity drops to half of the maximum value.
Coherence Length & Spectral Linewidth
There are two conversion formulas for the coherence length of the laser and the spectral linewidth:

1. L=λ2/Δλ (L: coherence length, λ: wavelength, Δλ: line width)

2. L=c/Δv (L: coherence length, c: speed of light, Δv: frequency width line width, Δv=Δλ*c/λ2)



There are many factors affecting the laser linewidth, such as optical confinement factor, output optical power, linewidth broadening factor, cavity loss and intracavity loss, grating structure, etc. The linewidth of the laser can be reduced by controlling these parameters. In the actual working process of the laser, the fluctuation of the frequency and phase of the laser will also have a great influence on the linewidth of the laser. Therefore, to obtain a narrow linewidth output with stable power, a good driving circuit and a well-designed structure are required. Reduce laser phase noise and frequency noise.



The smaller the value of the line width, the higher the purity of the spectrum, that is, the better the monochromaticity of the laser. Lasers with these characteristics typically have very little phase or frequency noise and little relative intensity noise. At the same time, the smaller the linewidth value of the laser is, the stronger the corresponding coherence is, which is manifested as an extremely long coherence length.

Classification of narrow linewidth lasers
1. Fiber Laser

Fiber lasers have high pump conversion efficiency, good beam quality, and high coupling efficiency. They are a hot research topic in the current laser field. In the context of the information age, fiber lasers have good compatibility with the current market fiber communication systems. Widely used in acoustics, seismic sensing, medical beauty, lidar, measurement, wind, security, experimental research and other fields.
2. Semiconductor laser

Compared with single-frequency fiber lasers, although there is still a certain gap in the line width of semiconductor lasers, semiconductor lasers have greater advantages than fiber lasers in terms of volume, power consumption, size and stability, so narrow Linewidth semiconductor lasers will have a wider range of applications. The ultra-small form factor package is the choice for OEM equipment, optical system design and integration, and end-user R&D.
3. Solid-state laser

The unique spatial structure characteristics of solid-state lasers make it more flexible in the design of narrow linewidth output. Several longitudinal mode selection methods can be combined as needed to improve the longitudinal mode selection accuracy, further narrow the linewidth, or introduce Non-linear frequency conversion and other means increase the intensity of mode competition, and expand the output wavelength of the laser while obtaining narrow linewidth operation, which is difficult for semiconductor and fiber lasers to achieve.