我自己来回答一下。。。
我设置的光源发散角太大,导致束腰比波长还要小,按照上图说法,不适合用POP,所以光斑大小测量不准确,是这样吧。。。大佬们指点一下。
图片出自:https://mp.weixin.qq.com/s?__biz=MzI5NDEyNjMwNQ==&mid=2650196847&idx=1&sn=06820ee59aea86a0836708bac97b0811&chksm=f465fce1c31275f7a1ed9582eb41aceb8b2583a85d315fe556e7a907f6b30d49fb0c27821ff3&mpshare=1&scene=1&srcid=0618GThFOLL587eOzkJkd2rE&sharer_shareinfo=9e62fa19c5d1eebffd12509afbd1eeed&sharer_shareinfo_first=9e62fa19c5d1eebffd12509afbd1eeed&exportkey=n_ChQIAhIQWQe%2BCB1lwY6xC7tVavMD7RL0AQIE97dBBAEAAAAAALVtAAqHrJUAAAAOpnltbLcz9gKNyK89dVj07g7SgRavoiEuZF8BCkzr1MFrLmhc0kElVeHK4HgcOZCFz4FqlUTe61vIOnf49wSXMFAnqYY0YfYTrLf48uKPt6hHTZJoNYrwNdB2Hfy0zMnLvZ78Ix3KqQ6OwmvKtBb%2FhmMjRdF%2F9sBykvX%2FMLJ%2FoPH1hgXrre7Cw2nlErh6amDejlgMh0kNX4F2rzgLY5pnBUd5DtKAucEHogjPRR%2BcZK6ES6JUl9fjI0c6baKX7pYoL1S9Obv4LW5oL3kuPKf1Z60pVXGAZ2C%2F6gTCIck%3D&acctmode=0&pass_ticket=JdRZLuxydS3AbYB3E6mTRZDyZRCRECszYhq505M%2Ftx2bt2MJR%2FS3WMxKq4%2FR83Iz&wx_header=0#rd