Polarization aberration caused by material birefringence can be partially compensated by lens clocking.In this Letter,we propose a fast and efficient clocking optimization method.First,the material birefringence distr...Polarization aberration caused by material birefringence can be partially compensated by lens clocking.In this Letter,we propose a fast and efficient clocking optimization method.First,the material birefringence distribution is fitted by the orientation Zernike polynomials.On this basis,the birefringence sensitivity matrix of each lens element can be calculated.Then we derive the rotation matrix of the orientation Zernike polynomials and establish a mathematical model for clocking optimization.Finally,an optimization example is given to illustrate the efficiency of the new method.The result shows that the maximum RMS of retardation is reduced by 64%using only 48.99 s.展开更多
Calcium fluoride is widely used in optical lithography lenses and causes retardation that cannot be ignored.However,few studies have been conducted to compensate for the retardation caused by calcium fluoride in optic...Calcium fluoride is widely used in optical lithography lenses and causes retardation that cannot be ignored.However,few studies have been conducted to compensate for the retardation caused by calcium fluoride in optical lithography systems.In this Letter,a new index based on orientation Zernike polynomials is established to describe the value of retardation.Then,a method of retardation compensation is described.The method is implemented by clocking calcium fluoride lens elements,and the optimal rotation angles are calculated using a population-based stochastic optimization algorithm.Finally,an example is provided to validate the method.展开更多
基金This work was supported by the National Science and Technology Major Project(No.2016ZX02201)the State Key Laboratory of Laser Interaction with Matter(No.SKLLIM1804)the Jilin Scientific and Technological Development Program(No.20190302050GX).
文摘Polarization aberration caused by material birefringence can be partially compensated by lens clocking.In this Letter,we propose a fast and efficient clocking optimization method.First,the material birefringence distribution is fitted by the orientation Zernike polynomials.On this basis,the birefringence sensitivity matrix of each lens element can be calculated.Then we derive the rotation matrix of the orientation Zernike polynomials and establish a mathematical model for clocking optimization.Finally,an optimization example is given to illustrate the efficiency of the new method.The result shows that the maximum RMS of retardation is reduced by 64%using only 48.99 s.
文摘Calcium fluoride is widely used in optical lithography lenses and causes retardation that cannot be ignored.However,few studies have been conducted to compensate for the retardation caused by calcium fluoride in optical lithography systems.In this Letter,a new index based on orientation Zernike polynomials is established to describe the value of retardation.Then,a method of retardation compensation is described.The method is implemented by clocking calcium fluoride lens elements,and the optimal rotation angles are calculated using a population-based stochastic optimization algorithm.Finally,an example is provided to validate the method.
