Characterization and inspection of microlens array by single cube beam splitter microscopy

Qu, Weijuan; Chee, Oi Choo; Yu, Yingjie; Asundi, Anand

doi:10.1364/ao.50.000886

Cited by 20 publications

(5 citation statements)

References 10 publications

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“…Digital holographic microscopy (DHM) is a label-free, noncontact, high resolution and full-field technique for measuring the surface profiles of nano-fabricated samples or the tomography of biological samples in the microscale with quantitative phase information [1]. Over recent decades, DHM has been fully developed and successfully applied in a wide range of applications, including live cell research [2,3], the characterization of MEMS or other microstructures [4][5][6][7], the inspection of micro-optics [8,9], and measurements of ternary diffusion [10].…”

Section: Introductionmentioning

confidence: 99%

LED-based digital holographic microscopy with slightly off-axis interferometry

Guo

Min

Zhou

et al. 2014

J. Opt.

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An LED illuminated Linnik-type digital holographic microscope (DHM) for high-quality phase imaging is presented by the adoption of slightly off-axis two-step blind-phase-shifting interferometry (TB-PSI). Slightly off-axis interferometry lowers the requirement on the angle between the object and the reference waves as well as the requirement on the resolving power of the charge-coupled device (CCD) camera. In addition, the apparatus is cost-effective and offers ease of alignment. The phase-shifting DHM is simply implemented by mechanically moving the reference mirror while disposing of a precise phase modulator such as a piezoelectric transducer (PZT). The phase shift between the two interferograms is extracted by Fourier transformation analysis, and then the phase image is reconstructed. The performance of the TB-PSI used in the scheme is analyzed. The phase imaging for nanostructured specimens is conducted, and the results demonstrate the feasibility of the scheme. The phase noise is reduced by 73% when compared to the result obtained with coherent illumination.

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Section: Introductionmentioning

confidence: 99%

LED-based digital holographic microscopy with slightly off-axis interferometry

Guo

Min

Zhou

et al. 2014

J. Opt.

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“…Over the past decades, thanks to newly available CCD cameras, high performance of computers, and advances in offline numerical processing techniques, DHM has been fully developed and successfully applied in diverse applications; for instance, in quantitative biology microscopy [2][3][4][5][6][7], surface relief characterization of MEMS or other microstructures [8][9][10][11][12], topography of micro-optics [13][14][15][16], and so on [17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Off-axis digital holographic microscopy with LED illumination based on polarization filtering

Guo¹,

Gao²,

Min³

et al. 2013

Appl. Opt.

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A reflection mode digital holographic microscope with light emitting diode (LED) illumination and off-axis interferometry is proposed. The setup is comprised of a Linnik interferometer and a grating-based 4f imaging unit. Both object and reference waves travel coaxially and are split into multiple diffraction orders in the Fourier plane by the grating. The zeroth and first orders are filtered by a polarizing array to select orthogonally polarized object waves and reference waves. Subsequently, the object and reference waves are combined again in the output plane of the 4f system, and then the hologram with uniform contrast over the entire field of view can be acquired with the aid of a polarizer. The one-shot nature in the off-axis configuration enables an interferometric recording time on a millisecond scale. The validity of the proposed setup is illustrated by imaging nanostructured substrates, and the experimental results demonstrate that the phase noise is reduced drastically by an order of 68% when compared to a He-Ne laser-based result.

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“…With the advantage of fast, nondestructive and full-field 3D measurement for reflecting or transmitted samples, digital holography has been widely used in many fields, such as vibration analysis, refractive index measurement, flow field visualization, microscopy, micro-optics and MEMS metrology, and so on [1][2][3][4][5][6][7][8][9] .…”

Section: Introductionmentioning

confidence: 99%

Dual wavelength digital holography for improving the measurement accuracy

et al. 2013

SPIE Proceedings

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In dual wavelength digital holography, a synthetic wavelength is obtained by using two lasers with different wavelengths to expand the measurement range of samples' step heights from nanometers to micrometers. However, its measurement accuracy reduces along with the expansion of measuring range and significant noise is introduced at the same time. For cases where the sample's height is smaller than the wavelength of illumination light, the measurement accuracy is very important. In this paper, a new approach of dual wavelength digital holography is presented. The synthetic wavelength is smaller than the wavelength of the two different lasers. Higher measurement accuracy can thus be achieved. The analysis and experimental results show the validity of this method.

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Characterization and inspection of microlens array by single cube beam splitter microscopy

Cited by 20 publications

References 10 publications

LED-based digital holographic microscopy with slightly off-axis interferometry

LED-based digital holographic microscopy with slightly off-axis interferometry

Off-axis digital holographic microscopy with LED illumination based on polarization filtering

Dual wavelength digital holography for improving the measurement accuracy

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