Divided-aperture subtraction-differential confocal method with nanoscale axial resolution

Shao, Rongjun; Zhao, Wenguang; Qiu, Lirong; Wang, Yun; Wu, Hanxu

doi:10.1364/ao.58.003252

Cited by 5 publications

(3 citation statements)

References 25 publications

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“…Consequently, they have experienced rapid development in surface non-contact measurement. As research in micro and nano-processing inspection continues to deepen, there is a growing need for precise imaging in complex testing environments involving samples with intricate compositions and structures [5][6] . Addressing the challenge of non-uniform reflection perturbation and noise perturbation resistance is crucial for improving existing confocal micro-imaging technology [7] .…”

Section: Introductionmentioning

confidence: 99%

Differential confocal microimaging with non-uniform reflection suppression

xiang,

Xie,

Cui

et al. 2024

International Conference on Mechatronic Engineering and Artificial Intelligence (MEAI 2023)

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A novel method for suppressing non-uniform reflection in differential confocal microimaging is proposed in this paper. The method is based on the differential confocal optical path and aims to eliminate the influence of non-uniform reflection perturbation on the surface contour imaging of highly stepped samples. This is achieved by dividing the squared difference between the pre-focus and post-focus signals of the differential confocal by the larger value of the squared pre-focus and post-focus signals. The effectiveness of the proposed method is demonstrated through theoretical analysis, simulation, and experimental verification. The results show that the method can successfully realize height imaging of height step samples. It is found that non-uniform reflection perturbation only affects the edge overshoot and position of the height profile imaging curve. This method can achieve high-precision, high-efficiency, and non-contact measurement of step samples with non-uniform reflection disturbances. This has significant implications for various applications requiring accurate surface contour imaging.

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Section: Introductionmentioning

confidence: 99%

Differential confocal microimaging with non-uniform reflection suppression

xiang,

Xie,

Cui

et al. 2024

International Conference on Mechatronic Engineering and Artificial Intelligence (MEAI 2023)

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“…To overcome this limitation, researchers have tried to eliminate the repetitive two-dimensional scanning process through approaches such as chromatic confocal microscopy (CCM), differential confocal microscopy (DCM), and divided-aperture differ ential confocal microscopy (DDCM). CCM, DCM, and DDCM encode the height information so that height can be calculated from the signal without axial scanning [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. First, CCM encodes the height of the sample surface spectrally in the axial direction.…”

Section: Introductionmentioning

confidence: 99%

“…DDCM combines the divided-aperture confocal microscopy and DCM. In other words, it uses the pupil plane of the objective lens, which is divided into illumination and collection to move the airy disc transversely on the detector plane when the object is translated axially, and it measures intensities with two point detectors that have a transverse offset from the optical axis because the linear relationship between the height of the sample surface and the differential signal can be used as a lookup table [21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Annular-beam dual-detection confocal reflectance microscopy for high-speed three-dimensional surface profiling with an extended volume

Lee

Gweon

Yoo

2020

Meas. Sci. Technol.

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In this study we propose an annular-beam dual-detection confocal reflectance microscopy (ADDCRM) method for high-speed three-dimensional surface measurements without longitudinal mechanical translation. ADDCRM can measure the axial position of a sample surface using the axial response curve ratio of two photodetectors, each with a different diameter pinhole. Since the height measurement range is limited by the full-width at halfmaximum of the ratio curve, an annular beam is used to extend the depth range without reducing the lateral resolution. The experimental results demonstrate that ADDCRM achieves high-speed surface profiling with a doubled-height measuring range compared to conventional Gaussian beams.

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