Enhancement of fluorescence collection efficiency of silicon carbide color center via femtosecond laser fabrication of internal micro-optical structures

In this paper, an innovative method is proposed to process micro-optical structures inside 4H-SiC by femtosecond laser to enhance the fluorescence collection efficiency of silicon vacancies. By creating internal micro-optical structures within the material, the direction of color center fluorescence emission was successfully adjusted, significantly enhancing the fluorescence emission efficiency. Experimental results demonstrate that the fluorescence intensity in the processed micro-structured region is 2.5 times that of the pristine sample. These microstructures not only improve the fluorescence lifetime and color center luminescence stability, but also enhance the spin properties. In addition, this method also shows significant potential in the rapid sensing of color centers. In rapid testing, the microstructured region exhibits a significant improvement in the signal-to-noise ratio of the ODMR spectrum, leading to a reduction of approximately 78 % in the fitting deviation of the spectral peak position. This study provides a novel method for the processing of internal micro-optical structures. This method also has greater potential. Through the design optimization of microstructures, the fluorescence collection efficiency of silicon vacancies can be further improved, which opens up new avenues for enhancing the sensitivity of SiC silicon vacancy quantum sensors.