Laser ablation of micro-photonic structures for efficient light collection and distribution

Shang, Xiaobing; Desmet, Andres; Smet, Jelle De; Joshi, Pankaj; Cuypers, Dieter; Put, Steven Van; Steenberge, Geert Van; Vervaeke, Michael; Thienpont, Hugo; Smet, Herbert De

doi:10.1088/0022-3727/48/24/245101

Cited by 4 publications

(3 citation statements)

References 18 publications

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“…The optical micro structures are fabricated using a technology based on laser ablation and soft embossing, as reported before 21 , 22 . The pitch and the height of the UV grating structure are experimentally found to be 50 μ m and 7.4 μ m, respectively, which closely approximate those of the master Epocore grating, as shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Fast switching cholesteric liquid crystal optical beam deflector with polarization independence

Shang¹,

Meeus²,

Cuypers³

et al. 2017

Sci Rep

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Optical beam deflectors based on the combination of cholesteric liquid crystals and polymer micro gratings are reported. Dual frequency cholesteric liquid crystal (DFCh-LC) is adopted to accelerate the switching from the homeotropic state back to the planar state. Polarization independent beam steering components are realized whose transmission versus the polarizing angle only varies 4.4% and 2.6% for the planar state and the homeotropic state, respectively. A response time of 451 ms is achieved for DFCh-LC-grating beam deflectors, which is fast compared to other nematic LC beam steerers with similar LC thickness.

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Section: Resultsmentioning

confidence: 99%

Fast switching cholesteric liquid crystal optical beam deflector with polarization independence

Shang¹,

Meeus²,

Cuypers³

et al. 2017

Sci Rep

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“…Fabrication of optical micro grating structures on glass substrates is the prerequisite for the target LC beam deflecting device. In this study, laser ablation with a nanosecond pulsed laser module of λ=248 nm is applied to the Epocore (micro resist technology GmbH) coated substrates, since it has a low ablation threshold (72±3 mJ cm −2 ) and a low surface roughness (R q <100 nm) [23]. The laser beam shaped by a mask with a triangular aperture is focused onto the Epocore polymer surface with a projection size of L×W=164×50 μm.…”

Section: Device Fabricationmentioning

confidence: 99%

Dual-frequency liquid crystal-polymer grating for fast response optical beam steering

Shang¹,

Cuypers²,

Fang³

et al. 2019

Smart Mater. Struct.

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In this study, we propose a liquid crystal (LC) beam deflector by combining dual frequency nematic LCs with optical micro structures. The total efficiency of up to 81% and 97%, are obtained for the beam steering state and the non-steering state, respectively. Optical micro gratings with fixed spacers are successfully fabricated using laser ablation and soft embossing. A dual frequency driving method is applied to the LC beam steering device for both the switching-on and the switching-off processes. The non-steering state is switched to the beam steering state rapidly with a duration as short as 3.8 ms, and the response time from the beam steering state to the non-steering state is achieved to be 20.5 ms, even when a thick LC layer with thickness of about 10 micron is required. The response behavior of this LC beam deflector can be further improved with the increase of the driving voltage or/and decrease of the LC thickness, which is very promising in quick response LC applications, such as dynamic lightings, autostereoscopic displays, optical communications etc.

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“…Laser ablation is a technology which combines photothermal and photochemical reactions to locally remove the undesired material from a solid surface by applying a number of laser pulses with a certain energy [6]. In this study, Epocore (micro resist technology GmbH) is used as the substrate material for the fabrication of optical structures, since it has a low ablation threshold (72±3 mJ/cm 2 ) and a good surface roughness (R q <100 *E-mail: xiaobing.shang@ugent.be nm) for laser ablation at Ȝ=248 nm [7]. The schematic diagram of the laser ablation process and its setup are illustrated in figure 1.…”

Section: Laser Ablation Of Polymer Micro Gratingsmentioning

confidence: 99%

68-2: Smart Liquid Crystal Beam Deflector With Laser Ablated Polymer Micro Grating Structure

Shang

Desmet

Joshi

et al. 2016

SID Symposium Digest of Technical Papers

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LC beam steering devices are realized using the combination of liquid crystal and polymer micro grating structures. The micro gratings are fabricated by combining two major techniques: laser ablation for a master mold and soft lithography for replicas with the desired optical materials. The LC components demonstrate effective beam deflections with a steering angle of 2.6° for both polarized monochromatic light (deflection efficiency >40%) and unpolarized white light beam (deflection efficiency >30%).

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Laser ablation of micro-photonic structures for efficient light collection and distribution

Cited by 4 publications

References 18 publications

Fast switching cholesteric liquid crystal optical beam deflector with polarization independence

Fast switching cholesteric liquid crystal optical beam deflector with polarization independence

Dual-frequency liquid crystal-polymer grating for fast response optical beam steering

68-2: Smart Liquid Crystal Beam Deflector With Laser Ablated Polymer Micro Grating Structure

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