Fs-laser based hybrid micromachining for polymer micro-opto electrical systems

Roth, Gian‐Luca; Haubner, Julian; Kefer, Stefan; Esen, Cemal; Hellmann, Ralf

doi:10.1016/j.optlaseng.2020.106362

Cited by 16 publications

(28 citation statements)

References 43 publications

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“…Comparable modifications have already been used in a transparent cycloolefin copolymer to generate waveguide‐coupled Bragg gratings. [ 52 ] The advantage of this approach is that a small period along the waveguide direction can be achieved as well as a large dimension perpendicular thereto with a considerably large modification volume. The disk‐shaped modifications are generated with an effective numerical aperture of 0.24 on the major axis and 0.015 on the minor axis, which results in an elliptical focal spot size of 1.9 µm × 24 µm.…”

Section: Resultsmentioning

confidence: 99%

“…Thus, we conclude that voids are lowering the effective refractive index

n_{e}

and disk‐shaped modifications increase the effective refractive index

n_{e}

as previously demonstrated for cyclic olefin copolymers. [ 52 ]…”

Section: Resultsmentioning

confidence: 99%

“…In addition to that, the SLM can be utilized to shape the beam in order to achieve an upright standing thin disk energy distribution. [ 52,70,71 ]…”

Section: Methodsmentioning

confidence: 99%

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Polymer Photonic Crystal Waveguides Generated by Femtosecond Laser

Roth

Kefer

Hessler

et al. 2021

Laser & Photonics Reviews

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Femtosecond laser‐based fabrication of integrated photonic crystal waveguides inside of a transparent polymer is reported. In general, the fabrication of waveguides based on femtosecond laser‐induced positive refractive index modifications is feasible. However, in transparent polymers their performance is limited since only minor refractive index changes can be achieved with this technique. These restrictions can be circumvented by generating hexagonal “photonic lattice like” waveguides, which consist of negative refractive index modifications in the cladding, enabling light confinement in the unirradiated core. A comprehensive study on the fabrication of this new class of polymer waveguide is performed as well as a characterization of its numerical aperture, mode field diameter, and attenuation. In addition, integration of Bragg gratings based on positive and negative refractive index modulations within the waveguide's core is studied. Moreover, we highlight that polymer photonic crystal waveguides are compatible with common femtosecond laser‐based internal structuring processes, enabling the creation of monolithic optofluidic devices, which is demonstrated by the fabrication of a Fabry–Pérot interferometer.

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Section: Resultsmentioning

confidence: 99%

“…Thus, we conclude that voids are lowering the effective refractive index

n_{e}

and disk‐shaped modifications increase the effective refractive index

n_{e}

as previously demonstrated for cyclic olefin copolymers. [ 52 ]…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Polymer Photonic Crystal Waveguides Generated by Femtosecond Laser

Roth

Kefer

Hessler

et al. 2021

Laser & Photonics Reviews

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“…[ 53–55 ] Furthermore, as already demonstrated by the authors, the employed laser‐based technology enables simultaneous generation of microstructures and microfluidic channels, which underlines the device's potential toward biomedical applications or micro‐opto‐electro‐mechanical systems. [ 41 ]…”

Section: Discussionmentioning

confidence: 99%

“…[ 39,40 ] Recently, the authors were able to transfer the generation of Cu conducting paths, via femtosecond laser reductive sintering (FLRS) of copper(II) oxide NPs, on COCs, thus paving the way toward a novel fabrication method for polymer‐based tunable photonic devices, such as selective wavelength reflectors or filters. [ 41 ]…”

Section: Introductionmentioning

confidence: 99%

Tunable Bulk Polymer Planar Bragg Gratings Electrified via Femtosecond Laser Reductive Sintering of CuO Nanoparticles

Kefer

Bischoff

Roth

et al. 2021

Advanced Optical Materials

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This contribution demonstrates and discusses electrically tunable polymer planar Bragg gratings based on bulk cyclic olefin copolymers. A lithographic single‐writing‐step method and femtosecond laser reductive sintering of copper(II) oxide nanoparticles are subsequently employed in order to generate buried photonic structures and copper conducting paths on top of the polymer substrate. This way, the necessary number of process steps for fabricating a planar polymer‐based electro‐optical device is greatly reduced. The response of a fully electrified grating structure follows temperature changes, induced by the copper conducting path, with sensitivities up to −31 pm K−1. Dilatometric measurements show that the specimen's behavior is correlated to the situationally reduced thermal expansion of the bulk polymer substrate. In consequence, the tuning response of the photonic platform follows a second order polynomial, whereas a direct current of 30 mA, which correlates to a power consumption of 18.3 mW, leads to a local temperature increase and a residual Bragg wavelength shift of 19.6 K and −547 pm, respectively. Moreover, the outstanding flexibility of the proposed fabrication concept is underlined by demonstrating alternative conducting path geometries, whereas one of the additional designs is adapted to control the spectral width of the Bragg grating's reflection peak.

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