Time-resolved imaging of flyer dynamics for femtosecond laser-induced backward transfer of solid polymer thin films

Feinaeugle, Matthias; Gregorčič, Peter; Heath, Daniel J.; Mills, B.; Eason, R.W.

doi:10.1016/j.apsusc.2016.11.120

Cited by 27 publications

(17 citation statements)

References 47 publications

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“…It was assumed that the use of such a scheme would lead to the appearance of microstructures on the back surface of the quartz plate in the form of a kind of "print". Previously, similar structures were formed in polyimide films [24,25].…”

Section: Methodssupporting

confidence: 54%

Laser-Induced Microstructuring of Polymers in Gaseous, Liquid and Supercritical Media

et al. 2021

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New results are presented for laser formation—in particular, the “drawing” of microstructures in polymer films using continuous-wave (CW) laser radiation λ = 405 nm with an intensity of 0.8–3.7 kW/cm2. The laser drawing was carried out in the polymer system poly-2,2′-p-oxydiphenylene-5,5′-bis-benzimidazole (OPBI), which consists of two phases: a solid polymer matrix with formic acid (HCOOH) dissolved in it. The formation of microstructures, including the stage of foaming, was carried out in three media: air, water and a supercritical carbon dioxide medium containing dissolved molecules of the silver precursor Ag(hfac)COD. The morphological features of foam-like track structures formed in the near-surface layer of the polymer films by laser “drawing” are considered. A model of processes is presented that explains the appearance of periodic structures. The key point of this model is that it considers the participation of the photoinduced mechanism of explosive boiling of formic acid molecules dissolved in the polymer matrix. Using Raman spectroscopy, spectra were obtained and interpreted, which relate to different stages in the formation of microstructures in OPBI films. The effects associated with the peculiarities of luminescent microstructures on the surfaces of glasses in close contact with polymer films during laser “painting” in the air have been studied.

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Section: Methodssupporting

confidence: 54%

Laser-Induced Microstructuring of Polymers in Gaseous, Liquid and Supercritical Media

et al. 2021

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“…Figure b shows a schematic representation of the mechanisms that lead to delamination and catapulting of microdiscs. An in‐depth analysis of the ejection dynamics of polymers by laser pulses has been reported in the context of LIFT, with results readily applicable to the present case. In short, the arrival of a single laser pulse at the donor, provided a sufficiently high laser fluence, induces the generation of a gas‐pocket at the donor–carrier substrate interface.…”

Section: Resultsmentioning

confidence: 74%

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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“…Efforts to address this issue include using lasers to delaminate and eject a disk from a film. Known in literature as laser decal transfer [18,19], laser catapulting [20,21] or simply a modified version of LIFT [22][23][24], it enables the transfer of material in solid form with no phase change involved. As shown in Figure 1, under appropriate conditions a single laser pulse mechanically ruptures a film, named donor, supported by a lasertransparent substrate, named carrier.…”

Section: Introductionmentioning

confidence: 99%