Combination of scanning probe technology with photonic nanojets

Duocastella, Martí; Tantussi, Francesco; Haddadpour, Ali; Zaccaria, Remo Proietti; Jacassi, Andrea; Veronis, Georgios; Diaspro, Alberto; Angelis, Francesco De

doi:10.1038/s41598-017-03726-5

Cited by 73 publications

(47 citation statements)

References 41 publications

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“…Instead, the MLA fabricated with LCP, and placed in close proximity to the wafer, enables to clearly resolve the structures. Combination of this strategy with sample translation could result in a cost‐efficient method to effectively decouple the classic tradeoff between field of view and spatial resolution of optical systems.…”

Section: Resultsmentioning

confidence: 99%

Single‐Shot Laser Additive Manufacturing of High Fill‐Factor Microlens Arrays

Surdo

Carzino

Diaspro

et al. 2018

Advanced Optical Materials

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Various methods have been adopted for the high-FF fabrication of MLA. Hexagonal arrays with 100% FF have been demonstrated by self-assembly methods based on dewetting, [7] localized water condensation, [8] or surface wrinkling, [9] but these approaches typically lack control in the design and positioning of the microlenses. In contrast, photolithography techniques have become the gold standard for the production of customized high-FF MLA. [10][11][12][13] Even if unrivaled industrial upscaling is possible, photolithography is optimized for planar substrates and requires multistep processing in expensive clean room facilities. More importantly, the need of masks imposes an additional limit in the degree of tunability of the MLA designs in timely fashion.Alternatively, direct-write technologies (DWTs) such as inkjet printing, [14] microdispensing, [15] two-photon polymerization, [16] laser-induced forward transfer (LIFT), [17,18] or multibeam interferencebased holography [19] enable the direct and maskless fabrication of polymeric microlenses and MLA with perfectly optical quality on a variety of substrates. In this case, though, the use of liquid prepolymers can result in merging of adjacent microlenses that seriously constraints the attainable FF of the arrays. [20] Recent works to improve the FF using DWTs include the fabrication of concave MLA using laser ablation followed by a replica molding step. [21,22] Despite excellent results in terms of uniformity and FF, this approach impedes the direct fabrication of MLA on substrates of interest. Furthermore, most DWTs require complex systems or ultrafast lasers for parallelization, which limit the overall throughput of these systems. Simply put, a low-cost and maskless technique capable of directly generating high-FF arrays at high-throughputs, with controlled geometry and at targeted positions on nonplanar substrates does not exist.In this work, we present a novel laser-based method for the realization of high-FF polymeric microlens arrays that addresses the limitations of traditional direct-write and photolithographic approaches. Our method, termed laser catapulting or LCP, exploits short (in the nanosecond scale) high-energy laser pulses to transfer polymeric solid microdiscs from a uniform film into targeted positions on a receiver substrate. After thermal reflow, namely the heating of the microdiscs above their glass transition temperature (T g ), planoconvex microlenses are obtained. Notably, the direct printing of discs in the solid-state enables the generation of highly close-packed High fill-factor microlens arrays (MLA) are key for improving photon collection efficiency in light-sensitive devices. Although several techniques are now capable of producing high-quality MLA, they can be limited in fill-factor, precision, the range of suitable substrates, or the possibility to generate arbitrary arrays. Here, a novel additive direct-write method for rapid and customized fabrication of high fill-factor MLA over a variety of substrates is demonstrated. This appro...

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Section: Resultsmentioning

confidence: 99%

Single‐Shot Laser Additive Manufacturing of High Fill‐Factor Microlens Arrays

Surdo

Carzino

Diaspro

et al. 2018

Advanced Optical Materials

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“…After obtaining the S/B ratio of the 2 images (with and without S/B enhancement), we quantified the relative enhancement introduced by our technique by computing the ratio between the 2 S/B values. We used a second metric to quantify our S/B enhancement by computing the contrast function C of each image according to :

C = \frac{I_{max} - I_{min}}{I_{max} + I_{min}},

…”

Section: Methodsmentioning

confidence: 99%

Enhanced volumetric imaging in 2‐photon microscopy via acoustic lens beam shaping

Piazza

Bianchini

Sheppard

et al. 2017

Journal of Biophotonics

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Three-dimensional imaging at high-spatiotemporal resolutions and over large penetration depths is key for unmasking the dynamics and structural organization of complex biological systems. However, the need to axially shift the focus, with consequent limitations in imaging speed, and signal degradation at large depths due to scattering effects, makes this task challenging. Here, we present a novel approach in 2-photon excitation microscopy that allows fast volumetric imaging and enhanced signal-to-background (S/B) in thick tissue. Our technique is based on ultrafast beam shaping at each pixel by means of an acoustic optofluidic lens. Shaping the excitation beam with different phase profiles enables both high-speed axial focus shifting, for continuous volumetric imaging, and controlled aberrated imaging, advantageous for out-of-focus background removal. We provide a theoretical description of our approach, and demonstrate volumetric imaging of neuronal cells from a mouse brain slice with enhancements in S/B up to a factor of 10 over a depth of 600 μm.

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“…To achieve large-area imaging at a controllable position, Li et al introduced a swimming micro-robot optical nanoscopy method based on chemically-powered microsphere lenses to realize stable and controllable scanning imaging [17]. Furthermore, microspheres attached to a glass micropipette [18,19] or AFM probe [20][21][22] were moved using a three-dimensional translation stage, so that images could be obtained at the desired position [23]. Although these methods have surpassed the limitation of the imaging field of view and expanded the imaging range, they are inefficient when using a single microsphere for imaging.…”

Section: Introductionmentioning

confidence: 99%