Thin film notch filters as platforms for biological image processing

Sulejman, Shaban B.; Priscilla, Niken; Wesemann, Lukas; Lee, Wendy S. L.; Lou, Jieqiong; Hinde, Elizabeth; Davis, Timothy J.; Roberts, Ann

doi:10.1038/s41598-023-31528-5

Cited by 8 publications

(3 citation statements)

References 45 publications

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“…It should be noted that single optical interfaces, as well as stacks of optically thin films, commonly exhibit transmission and reflection properties that enable phase visualization techniques that fall into this category. ,− In this Perspective, however, we exclusively focus on approaches based on metasurfaces and gratings.…”

Section: Metasurface-enabled Phase Imaging Methodsmentioning

confidence: 99%

New Avenues for Phase Imaging: Optical Metasurfaces

Priscilla,

Sulejman,

Roberts

et al. 2024

ACS Photonics

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Visualizing the phase of an optical field is fundamental to applications ranging from biological microscopy through to material science. Its importance is evidenced by the award of the 1953 Nobel Prize to Frits Zernike for his invention of the phase contrast microscope. Conventional phase imaging techniques, including Zernike phase contrast, differential interference contrast, and interferometry, often rely on bulky optical components and macroscopic propagation distances. These factors hinder the miniaturization and integration into ultracompact imaging systems. Furthermore, computational methods also present challenges due to computational complexity, potentially compromising speed and energy efficiency. The recent emergence of the use of nano-optics, including thin films and metasurfaces, in image processing has opened up possibilities for a new class of compact methods for phase imaging. These nanostructured devices have been shown to permit phase visualization, and we believe that they hold the potential to enable the next generation of imaging systems and photodetectors in a broad range of applications.

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Section: Metasurface-enabled Phase Imaging Methodsmentioning

confidence: 99%

New Avenues for Phase Imaging: Optical Metasurfaces

Priscilla,

Sulejman,

Roberts

et al. 2024

ACS Photonics

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“…I max − I min I max + I min (1) where I max is the maximum light intensity of the image and I min is the minimum light intensity.…”

Section: Contrast =mentioning

confidence: 99%

“…Notch filters can be applied to visual optics to improve image contrast. Recently, Sulejman et al [1] presented the application of commercially available thin-film spectral notch filters to phase-contrast imaging of transparent samples. They demonstrated enhanced contrast imaging of wavefields introduced by spatial light modulators and unstained biological samples.…”

Section: Introductionmentioning

confidence: 99%

Optical Interference Filters Combined with Thin Film Residual Stress Compensation for Image Contrast Enhancement

Tien

Cheng

et al. 2023

Coatings

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We propose two single-wavelength notch filters and one dual-wavelength (480 and 620 nm) notch filter to enhance image contrast. The stack structure of the notch filters was designed as (Ta2O5/SiO2)4Ta2O5 in Essential Macleod thin film simulation software. Dual-electron-beam evaporation with ion beam-assisted deposition was used to prepare optical interference filters with different center wavelengths. A multilayer notch filter with a center wavelength of 620 nm was deposited on the front surface of the glass, and then a notch filter with a center wavelength of 480 nm was coated on the rear surface of the same glass. The proposed dual-wavelength (480 and 620 nm) notch filter is a combination of two single-wavelength notch filters coated on a double-sided glass substrate to compensate for residual stress. The transmittance, residual stress, and surface roughness of the proposed notch filter were evaluated using different measuring instruments. The experimental results show that the residual stress of the dual-wavelength notch filter could be reduced to 10.8 MPa by using a double-sided coating technique. The root-mean-square (RMS) surface roughness of the notch filters was measured by using a Linnik microscopic interferometer. The RMS surface roughness was 1.80 for the 620 nm notch filter and 2.09 for the 480 nm notch filter. The image contrast obtained with the three different notch filters was measured using an optical microscope and a CMOS camera. The contrast value could be increased from 0.328 (without a filter) to 0.696 (dual-wavelength notch filter).

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