An approach to achieve lateral superresolution for small probe confocal measurement system and its element

作者：Zhao WQ^*; Li Q; Qiu LR; Tan JB; Wang Q

来源：Optik, 2005, 116(12): 557-562.

DOI：10.1016/j.ijleo.2005.05.004

• superresolution
• confocal microscopy
• binary optical
• surface measurements

A shaped annular beam superresolution approach is proposed to improve a lateral resolution of a small probe laser confocal measurement system (LCMS). The approach proposed enables lateral superresolution measurement of LCMS to be achieved by using a binary optical diffractive element to shape a He-Ne Gaussian laser beam into an annular beam with an inner diameter of 0.87mm and an outer diameter of 1.8mm required for superresolution measurement, and shift the beam spatial frequency from low to high. And a binary optical element (BOE) with 16 phase levels is designed and fabricated to shape a Gaussian laser beam into an annular beam. Preliminary experimental results indicate that an intensity distribution of a shaped annular beam is in agreement with simulation results, the diffractive efficiency is 87.2%, LCMS lateral and axial resolutions of 0.2 mu m and 3 nm are achieved, respectively, and its measurement range is expanded nearly to double, when BOE is used in LCMS and lambda = 0.6328 mu m. NA = 0.85.

• 出版日期2005
• 单位哈尔滨工业大学