Liu Jian, Zhao Weisong, Liu Chenguang, Kong Chenqi, Zhao Yixuan, Ding Xiangyan, Tan Jiubin
Center of Ultra-precision Optoelectronic Instrument Engineering, Harbin Institute of Technology, No. 2, Yikuang Str., Nangang District, Harbin 150080, China.
National Key Laboratory of Tunable Laser Technology, Harbin Institute of Technology, Harbin 150001, China.
Rev Sci Instrum. 2019 May;90(5):053703. doi: 10.1063/1.5088102.
Confocal microscopy has the advantages of high resolution and optical sectioning ability over conventional microscopy. However, aberration induced by the optical system can compromise these advantages and considerably reduce the energy reaching the pointlike detector. We propose an accurate aberration correction method with a liquid-crystal spatial light modulator (LCSLM) in the confocal system. Each coefficient of Zernike aberration modes is calculated by directly measuring the variance of the images with different bias aberration modes. Large-coefficient (>0.7 rad) aberration is compensated first by LCSLM, following which aberrations with small coefficients are measured precisely, minimizing the cross talk between different kinds of aberrations. With this predistortion strategy, the aberration correction is much more accurate, and maximum image intensity in the normal and nonconjugated systems is improved by 2.5 times and 4 times compared to the normal correction method, respectively, demonstrating the effectiveness of our method.
