Researchers from the Chinese Academy of Sciences, led by Huanhuan Wu, have proposed a novel method for broadening the spectrum of ultraviolet lasers using ultrafast-rotating phase plates (URPPs). This technique could have significant implications for the energy sector, particularly in inertial fusion energy and optical frequency comb applications.
The researchers’ scheme involves using rapidly rotating phase plates to induce a Doppler frequency shift in ultraviolet lasers. This shift results in continuous spectral broadening. For instance, with a disk-shaped phase plate of a certain size and rotation speed, the team achieved a spectral broadening of 0.07%. By increasing the rotation speed or reducing the size of the phase elements, even greater spectral broadening can be achieved.
Moreover, the researchers found that arranging multiple URPPs in series enhances the spectral broadening effect. This superimposed spatiotemporal modulation leads to more effective speckle smoothing, which is crucial for improving the quality and stability of laser beams used in energy applications.
One of the most promising practical applications of this research is in inertial fusion energy. Laser-plasma instabilities can hinder the efficiency of inertial fusion reactions. The spectral broadening achieved through this method could help mitigate these instabilities, potentially improving the viability of inertial fusion as a clean energy source.
Another potential application is in optical frequency combs, which are used in various precision measurement and sensing applications. The ability to broaden the independent spectrum of these combs could enhance their precision and utility in energy-related research and development.
This research was published in the journal Optics Express, a publication of The Optical Society. While the study is still in its early stages, the proposed method offers a promising avenue for advancing laser technology in the energy sector. Further research and development will be needed to fully realize the potential of this technique.
This article is based on research available at arXiv.