US 11,668,625 B2
Apparatus and method for detecting wavefront aberration of objective lens
Peng Li, Shanghai (CN); Feng Tang, Shanghai (CN); Xiangzhao Wang, Shanghai (CN); Yunjun Lu, Shanghai (CN); Yang Liu, Shanghai (CN); Xiangyu Wei, Shanghai (CN); Yisha Cao, Shanghai (CN); and Changzhe Peng, Shanghai (CN)
Assigned to Shanghai Institute of Optics and Fine Mechanics, ChineseAcademy of Sciences, Shanghai (CN)
Filed by Shanghai Institute of Optics And Fine Mechanics, Chinese Academy of Sciences, Shanghai (CN)
Filed on Sep. 10, 2021, as Appl. No. 17/472,047.
Claims priority of application No. 202110302284.X (CN), filed on Mar. 22, 2021.
Prior Publication US 2022/0299402 A1, Sep. 22, 2022
Int. Cl. G01B 11/02 (2006.01); G01M 11/02 (2006.01); G01B 9/0209 (2022.01); G02B 5/08 (2006.01)
CPC G01M 11/0271 (2013.01) [G01B 9/0209 (2013.01); G02B 5/08 (2013.01)] 3 Claims
OG exemplary drawing
 
1. A method for detecting wavefront aberration of an objective lens to be detected by using an apparatus comprising a wavefront detection system (1), a planar mirror (3) with an angle the planar mirror (3) tilts at relative to an optical axis of the wavefront detection system (1), a planar mirror adjusting mechanism (4) bearing the planar mirror (3), and an objective lens (2) placed between the wavefront detection system (1) and the planar mirror (3), comprising:
step (1) enabling a test wavefront emitted by the wavefront detection system (1) to pass through the objective lens (2) and using (xIN,yIN) to denote an intersection point of the test wavefront and a pupil plane of the objective lens (2);
step (2) adjusting the planar mirror adjusting mechanism (4) so that the planar mirror (3) is positioned at a focal point of the objective lens (2), wherein the test wavefront passes through the objective lens (2) and arrives upon the planar mirror (3), a reflected wavefront reflected by the planar mirror (3) passes through the objective lens (2) again and is received by the wavefront detection system (1); and using (x1OUT, y1OUT) to denote an intersection point of the reflected wavefront and the pupil plane of the objective lens (2);
step (3) detecting, by the wavefront detection system (1), the reflected wavefront, calculating and deriving phase information
Wt1(x1OUT, y1OUT)=Wlens(xIN, yIN)+Wlens(x1OUT, y1OUT), wherein Wlens is wavefront aberration of the objective lens (2);
step (4) adjusting, by the planar mirror adjusting mechanism (1), so that the planar mirror (3) is positioned at the focal point of the objective lens (2) and the angle the planar mirror (3) tilts at is changed, wherein the wavefront detection system (1) receives and detects the reflected wavefront Wt2 when the angle is changed;
step (5) repeating step (4), recording the reflected wavefronts Wtn received and detected by the wavefront detection system (1) under different angles the planar mirror (3) tilts at, wherein n is an integer that is greater than or equal to 3 and indicates a sequence of the different angles;
step (6) selecting an m-term polynomial Pi for fitting the wavefront aberration of the objective lens (2), and calculating a polynomial
Pni(xnOUT, ynOUT)=Pi(cIN,yIN)+Pi(xnOUT, ynOUT), i=1˜m corresponding to each reflected wavefront Wtn according to the angle the planar mirror (3) tilts at;
step (7) calculating a polynomial coefficient Cm of the wavefront aberration of the objective lens (2) corresponding to the polynomial Pm through a formula as follows:

OG Complex Work Unit Math
wherein Pcolni and Wtcoln are column vectors of Pni and Wtn, respectively; and
step (8) deriving a result of fitting expressed by polynomial Pi on basis of the polynomial coefficient Cm.