Jiazhu Duan

Detecting subsurface defects in optical components has always been challenging. This study utilizes laser scattering and photothermal weak absorption techniques to detect surface and subsurface nano-damage precursors of single-crystal silicon components. Based on laser scattering and photothermal weak absorption techniques, we successfully establish the relationship between damage precursors and laser damage resistance. The photothermal absorption level is used as an important parameter to measure the damage resistance threshold of optical elements. Single-crystal silicon elements are processed and post-processed optimally. This research employs dry etching and wet etching techniques to effectively eliminate damage precursors from optical components. Additionally, detection techniques are utilized to comprehensively characterize these components, resulting in the successful identification of optimal damage precursor removal methods for various polishing types of single-crystal silicon components. Consequently, this method efficiently enhances the damage thresholds of optical components.

We propose and experimentally demonstrate a silicon PCRR with a high Q factor. By manipulating the radii and locations of the key holes, the tangential k-vector component inside the leaky region could be effectively reduced. Consequently, the theoretical and experimental Q factors are significantly improved to 7.28×10 ⁵ and 2.44×10 ⁵ , respectively. To the best of our knowledge, it is the highest Q factor of the silicon PCRRs with such a compact size. Owing to the dominant advantages of high- Q factors, compact size (81 μm ² ) and complementary metal-oxide semiconductor (CMOS)-compatibility, the proposed silicon PCRRs are favorable for on-chip low-threshold lasers and channel drop filters.