Question

Compensators move out of limit

  • 17 May 2021
  • 0 replies
  • 105 views

Hi,


I am modeling an asymmertrical system for laser line excitation. The symmetry is broken by a Powell lens to create a top-hat illumination on the sample. The last element is a microscope objective (paraxial surface) after which the beam somewhat evenly irradiates the image plane along x-plane and is close to diffraction limit along the y-plane.


I began tolerancing the system, includes a zoom triplet, and cylindrical afocal beam expansion and etc. I hope to achive diffractin limit along the y-plane, to do so i set two elements as compensators. When i set y-spot for tolerance criterion it seems to be working, however if i set the merit fucntion, that is defined for RMS y-spot, the compensator moves way out of its working limits and gives better (but false) results.


Anybody can explain what is the difference and what part am i missing?


Thank you,


Zsombor


 


Part of the result:


Compensator: Thickness 8, Min = -1,0000, Max = 1,0000


Compensator: Thickness 22, Min = -0,5000, Max = 0,5000


WARNING: Boundary constraints on compensators will be ignored.


Criterion : User defined merit function


Mode : Sensitivities


Optimization Cycles : 5


Nominal Criterion : 0,00117646



Estimated Performance Changes based upon Root-Sum-Square method:


Nominal Merit Function : 0,00117646


Estimated change : 0,00686855


Estimated Merit Function : 0,00804501


Compensator Statistics:


Thickness Surf 8:


Nominal : 9,924658


Minimum : -2,262563


Maximum : 29,530714


Mean : 9,800469


Standard Deviation : 3,409756


Thickness Surf 22:


Nominal : 12,660230


Minimum : 10,268682


Maximum : 80,473917


Mean : 13,678104


Standard Deviation : 6,776885


End of Run.


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