Confocal microscopy with a microlens array

Yu, Yinchuan; Ye, Xianjun; McCluskey, M. D.

doi:10.1364/ao.386269

Cited by 9 publications

(5 citation statements)

References 24 publications

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“…Currently, no commercial tool exists that can perform this characterization, therefore, the microscope described henceforth was built to independently characterize various micro-optical technologies, both refractive and diffractive alike, on a fair and consistent basis. While it is not uncommon for researchers to design a custom microscope to examine micro-optical elements [9][10][11][12], it was determined that previously published designs would be insufficient to examine the criteria for a fair comparison of the various microlens technologies of interest. Certain design choices implemented by this microscope were made for relevance to the APD technology format that was used for the monolithic integration.…”

Section: Motivation and Backgroundmentioning

confidence: 99%

Microscope design for direct optical characterization of various microlens technologies

Kranefeld,

Carlson,

Nothern

et al. 2024

Photonic Instrumentation Engineering XI

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Microlens arrays (MLA) are a critical component of avalanche photodiode (APD) technology, but their performance is rarely characterized or investigated independent of the photodetector. To understand how best to improve coupling, the MLA must be characterized and compared to other technologies on a fair and consistent basis. In order to investigate new designs and compare different types of microlens technologies, a custom microscope was built. This microscope was designed to image the MLA surface as well as its focused beam which required solutions to the following challenges: 6axis manipulation of the sample, sub-micron positional resolution, perpendicular travel to the optical axis, brightfield imaging, multispectral imaging, image processing, uniform irradiance over the sample area, and calibrated absolute optical power measurements. This microscope design enables the focal length range to be mapped with sub-micron accuracy along the paraxial ray. The imaged beam spot is quantitatively analyzed in MATLAB for 1/e 2 diameter and encircled energy, as well as qualitatively with complementary data sets. It was shown that Fresnel lens and plano-convex refractive MLA designs from various material groups could be compared equally in a side-by-side comparison.

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Section: Motivation and Backgroundmentioning

confidence: 99%

Microscope design for direct optical characterization of various microlens technologies

Kranefeld,

Carlson,

Nothern

et al. 2024

Photonic Instrumentation Engineering XI

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show abstract

“…Confocal microscopy is a popular imaging modality known for its optical sectioning capability [1]. Multifocal illumination, an enhancement to confocal imaging, improves signal-to-noise ratio and image acquisition speed [2]. Typically, Gaussian beam distributions are used, but they result in non-uniform illumination fields [3].…”

Section: Introductionmentioning

confidence: 99%

“…Typically, Gaussian beam distributions are used, but they result in non-uniform illumination fields [3]. Alternatively, a Super Gaussian (SG) beam, when applied to a Micro Lens Array (MLA), creates a homogeneous array of focal spots [2]. By encoding SG beam amplitudes onto Lee holograms, volume holographic (VH) beam shapers can produce uniform intensity distributions [3].…”

Section: Introductionmentioning

confidence: 99%

Advanced 3D imaging: a volume holography-based approach to multi-point laser scanning confocal microscopy

Suresh,

Vyas,

Yeh

et al. 2024

Photosensitive Materials and Their Applications III

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In confocal microscopy, multifocal illumination can reduce image capture time compared to single point scanning. However, due to increased system complexity, attaining uniform multifocal illumination across the field of view with traditional approaches is difficult. For multifocal confocal imaging in lateral as well as in axial directions, we propose two methods using a volume holographic lenslet array illuminator (VHLAI) and a volume holographic axial multi-plane illuminator (VHAMI) respectively. A super Gaussian (SG) beam shaping was incorporated with VHLAI with a 43% efficiency and utilized in a confocal microscope to provide uniform array illumination. Multiplexed holographic gratings are used to achieve simultaneous multi-plane illumination. Multiple photo detector arrangements have been done to carry out simultaneous multi-plane imaging without mechanical or electro-optic axial scanning. The design methodologies for photopolymer-based volume holographic beam shapers are discussed, as well as their benefits. we demonstrate the ability of proposed approaches by comparing optically sectioned microscopic images of fluorescence beads, florescence pollen grains, and biological specimens to wide-field images. The proposed systems can greatly reduce image acquisition time while maintaining image quality. When compared to former spatial light modulating devices, the illumination approach employed in our confocal systems are more direct and compact. Multifocal illumination may considerably shorten scanning time without requiring a change in scanning devices, while also providing uniform illumination across the field of view. These multifocal confocal systems construct images more quickly while requiring no modifications to scanning hardware. The approaches shown here might be useful in high-speed multifocal microscopy platforms.

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“…Microlens arrays (MLAs) have attracted significant interest from diverse industries and academia owing to their wide range of applications, including optical and image sensors, display components, and microscopes [1][2][3][4][5][6][7][8][9]. The shape, dimensions, and array of the MLA are considered highly important parameters because they directly influence the optical path through the MLA, subsequently impacting the device performance [10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Development of Shape Prediction Model of Microlens Fabricated via Diffuser-Assisted Photolithography

Kim,

Shin,

Seo

2023

Micromachines

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The fabrication of microlens arrays (MLAs) using diffuser-assisted photolithography (DPL) has garnered substantial recent interest owing to the exceptional capabilities of DPL in adjusting the size and shape, achieving high fill factors, enhancing productivity, and ensuring excellent reproducibility. The inherent unpredictability of light interactions within the diffuser poses challenges in accurately forecasting the final shape and dimensions of microlenses in the DPL process. Herein, we introduce a comprehensive theoretical model to forecast microlens shapes in response to varying exposure doses within a DPL framework. We establish a robust MLA fabrication method aligned with conventional DPL techniques to enable precise shape modulation. By calibrating the exposure doses meticulously, we generate diverse MLA configurations, each with a distinct shape and size. Subsequently, by utilizing the experimentally acquired data encompassing parameters such as height, radius of curvature, and angles, we develop highly precise theoretical prediction models, achieving R-squared values exceeding 95%. The subsequent validation of our model encompasses the accurate prediction of microlens shapes under specific exposure doses. The verification results exhibit average error rates of approximately 2.328%, 7.45%, and 3.16% for the height, radius of curvature, and contact angle models, respectively, all of which were well below the 10% threshold.

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Confocal microscopy with a microlens array

Cited by 9 publications

References 24 publications

Microscope design for direct optical characterization of various microlens technologies

Microscope design for direct optical characterization of various microlens technologies

Advanced 3D imaging: a volume holography-based approach to multi-point laser scanning confocal microscopy

Development of Shape Prediction Model of Microlens Fabricated via Diffuser-Assisted Photolithography

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