Detection of Subsurface Damage Morphology of Lapped Optical Components by Analysis of the Fluorescence Lifetimes of Quantum Dots

Abstract

Optical components inevitably suffer subsurface damage (SSD) during grinding and lapping, and this SSD substantially degrades the performance of optical systems. Moreover, given the surface roughness of optical components after grinding or lapping, it is impossible to non-destructively and accurately detect SSD generated by these processes, especially regarding the morphological details of such SSD. Accordingly, a novel method for detecting the morphological details of SSD in lapped optical components via analysis of the fluorescence lifetimes of quantum dots (QDs) is developed. This paper shows that, (1) compared with other methods, this novel method detects more morphological details of SSD in lapped optical components and that this detection is unaffected by the elemental composition/size/fluorescence lifetime of the QDs; (2) SSD detection achieved by analyzing the QD fluorescence lifetime can detect more SSD details on the premise of achieving the detection of SSD distribution and depth; and (3) the SSD in lapped optical components exhibits textural features, and “hole”-type SSD is detected in addition to “solid”-point and strip SSD. These findings will facilitate research on the formation mechanism of SSD, thereby enabling improvements in optical manufacturing techniques.