Diffractive lens design for optimized focusing

Wan, Xiaowen; Shen, Bing; Menon, Rajesh

doi:10.1364/josaa.31.000b27

Cited by 27 publications

(10 citation statements)

References 21 publications

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“…Diffractive optics, on the other hand, may be planar and lightweight 1 . However, conventional diffractive optics are not typically used for imaging because of significant off-axis and chromatic aberrations 2 , 3 as well as low broadband focusing efficiencies. Recently, planar metalenses have been used for imaging 4 , 5 .…”

Section: Introductionmentioning

confidence: 99%

Broadband imaging with one planar diffractive lens

Mohammad

Meem

Shen

et al. 2018

Sci Rep

Self Cite

119

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We demonstrate imaging over the visible band using a single planar diffractive lens. This is enabled via multi-level diffractive optics that is designed to focus over a broad wavelength range, which we refer to as an achromatic diffractive lens (ADL). We designed, fabricated and characterized two ADLs with numerical apertures of 0.05 and 0.18. Diffraction-limited focusing is demonstrated for the NA = 0.05 lens with measured focusing efficiency of over 40% across the entire visible spectrum (450 nm to 750 nm). We characterized the lenses with a monochromatic and a color CMOS sensor, and demonstrated video imaging under natural sunlight and other broadband illumination conditions. We use rigorous electromagnetic simulations to emphasize that ADLs can achieve high NA (0.9) and large operating bandwidth (300 nm in the visible spectrum), a combination of metrics that have so far eluded other flat-lens technologies such as metalenses. These planar diffractive lenses can be cost-effectively manufactured over large areas and thereby, can enable the wide adoption of flat, low-cost lenses for a variety of imaging applications.

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Section: Introductionmentioning

confidence: 99%

Broadband imaging with one planar diffractive lens

Mohammad

Meem

Shen

et al. 2018

Sci Rep

Self Cite

119

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“…The conventional diffractive lens (zone-plate), on the other hand, exhibits opposite chromatic aberration ( Fig. 1(b) ) 6 7 8 . Diffraction angle is proportional to wavelength 2 , and thus longer wavelengths are focused closer than shorter ones.…”

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confidence: 99%

Chromatic-aberration-corrected diffractive lenses for ultra-broadband focusing

Wang

Mohammad

Menon

2016

Sci Rep

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183

135

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We exploit the inherent dispersion in diffractive optics to demonstrate planar chromatic-aberration-corrected lenses. Specifically, we designed, fabricated and characterized cylindrical diffractive lenses that efficiently focus the entire visible band (450 nm to 700 nm) onto a single line. These devices are essentially pixelated, multi-level microstructures. Experiments confirm an average optical efficiency of 25% for a three-wavelength apochromatic lens whose chromatic focus shift is only 1.3 μm and 25 μm in the lateral and axial directions, respectively. Super-achromatic performance over the continuous visible band is also demonstrated with averaged lateral and axial focus shifts of only 1.65 μm and 73.6 μm, respectively. These lenses are easy to fabricate using single-step grayscale lithography and can be inexpensively replicated. Furthermore, these devices are thin (<3 μm), error tolerant, has low aspect ratio (<1:1) and offer polarization-insensitive focusing, all significant advantages compared to alternatives that rely on metasurfaces. Our design methodology offers high design flexibility in numerical aperture and focal length, and is readily extended to 2D.

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“…Clearly suppressed sidelobes were observed with an intensity less than 26% of the focal spot intensity. Other designs of SOLs that utilize BP 66 and BAP 67 masks were also reported for circularly polarized light.…”

Section: Superoscillatory Optical Devicesmentioning

confidence: 99%

Superoscillation: from physics to optical applications

2019

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The resolution of conventional optical elements and systems has long been perceived to satisfy the classic Rayleigh criterion. Paramount efforts have been made to develop different types of superresolution techniques to achieve optical resolution down to several nanometres, such as by using evanescent waves, fluorescence labelling, and postprocessing. Superresolution imaging techniques, which are noncontact, far field and label free, are highly desirable but challenging to implement. The concept of superoscillation offers an alternative route to optical superresolution and enables the engineering of focal spots and point-spread functions of arbitrarily small size without theoretical limitations. This paper reviews recent developments in optical superoscillation technologies, design approaches, methods of characterizing superoscillatory optical fields, and applications in noncontact, far-field and label-free superresolution microscopy. This work may promote the wider adoption and application of optical superresolution across different wave types and application domains.

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Diffractive lens design for optimized focusing

Cited by 27 publications

References 21 publications

Broadband imaging with one planar diffractive lens

Broadband imaging with one planar diffractive lens

Chromatic-aberration-corrected diffractive lenses for ultra-broadband focusing

Superoscillation: from physics to optical applications

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