Zhiying Yang

1 Introduction Peatlands store approximately one third of the global soil carbon (ca. 650 Gt C) [1-3] and play a key role in atmospheric CO2 drawdown and climate change mitigation [2, 4]. Dissolved organic carbon (DOC) export represents a major pathway of carbon loss from peatlands, constituting up to 50% of net ecosystem CO2 exchange therein [5, 6]. Moreover, peatlands export more DOC than any other terrestrial ecosystem, accounting for 20% of the DOC ultimately transferred from land to sea [7].

Through theoretical analysis, this study validates the feasibility of wavefront coding (WFC) technology for simultaneously extending the depth of field (DOF) and the operational temperature range. We designed and optimized an industrial endoscope with an image space F-number of 8, an effective focal length of 7 mm, a total length of 871 mm, and a field of view of 52°. To achieve a larger DOF and athermalization over a wider temperature range, an expanded quintic phase mask is introduced.