“…So far, based on different kinds of mechanisms and writing methods, many LPGs have been fabricated in SM and MM POF, SI and GI POF, as well as mPOFs as listed in Table 4 [48,67,71,72,73,75,76,78,79,82,84,87,109,110,123,135,136,138,142,147]. The point-by-point technique is the most used method used for POF LPG fabrication.…”