Shaobo Gao, Vishnu Kavungal, Shuma Oya, Daichi Okuno, Ezra Kassa, William J Hughes, Peter Horak, Hiroki Takahashi
An erratum of [Opt. Express33, 39009 (2025)10.1364/OE.564341]: the measured cavity finesses were overestimated by a factor of two, due to a programming error in a fitting function used in the cavity finesse analysis, which led to an underestimation of the cavity loss by a factor of two. The newly confirmed cavity loss deviates from our previous estimation. We performed additional measurements and confirmed that the mirror coating losses are higher than previously expected. Nonetheless, we observe no additional loss attributed to our machining method, e.g., through surface roughness or profile deviation. Thus, our main results and conclusions in the paper are unaffected.