New Research on narrow-linewidth laser
Narrow-linewidth laser are crucial in a wide range of applications such as precision sensing, spectroscopy, and quantum science. In addition to spectral width, spectral shape is also an important factor, which depends on the application scenario. For instance, the power on both sides of the laser line might introduce errors in the optical manipulation of qubits and affect the accuracy of atomic clocks. In terms of laser frequency noise, the Fourier components generated by spontaneous radiation entering the laser mode are usually higher than 105 Hz, and these components determine the amplitudes on both sides of the line. Combining the Henry enhancement factor and other factors, the quantum limit, namely the Schawlow-Townes (ST) limit, is defined. After eliminating technical noises such as cavity vibration and length drift, this limit determines the lower limit of the achievable effective line width. Therefore, minimizing quantum noise is a key step in the design of narrow-linewidth lasers.
Recently, researchers have developed a new technology that can reduce the linewidth of laser beams by more than ten thousand times. This research may completely transform the fields of quantum computing, atomic clocks and gravitational wave detection. The research team utilized the principle of stimulated Raman scattering to enable lasers to excite higher-frequency vibrations within the material. The effect of narrowing the linewidth is thousands of times higher than that of traditional methods. Essentially, it is equivalent to proposing a new laser spectral purification technology that can be applied to a variety of different types of input lasers. This represents a fundamental breakthrough in the field of laser technology.
This new technology has solved the problem of minute random light wave timing changes that cause the purity and accuracy of laser beams to decline. In an ideal laser, all light waves should be perfectly synchronized – but in reality, some light waves are slightly ahead of or behind others, causing fluctuations in the phase of the light. These phase fluctuations generate “noise” in the laser spectrum – they blur the laser’s frequency and reduce its color purity. The principle of Raman technology is that by converting these temporal irregularities into vibrations within the diamond crystal, these vibrations are rapidly absorbed and dissipated (within a few trillionths of a second). This makes the remaining light waves have smoother oscillations, thus achieving higher spectral purity and generating a significant narrowing effect on the laser spectrum.
Post time: Aug-04-2025