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1.
Appl Opt ; 61(8): 1863-1875, 2022 Mar 10.
Article in English | MEDLINE | ID: mdl-35297875

ABSTRACT

We discuss and describe the development of an origination process for planar free-form micro-optical elements from a given optical design. The targeted masters serve as origination structures for a roll-to-roll mass fabrication process. Specifically targeted are complex, optically smooth, surface relief structures with variable structure heights in the range of 1-20 µm, with typical lateral sizes of more than 5 µm. The area of the targeted masters is in the range of 1cm2. The main part of the paper is devoted to the description of a self-developed grayscale laser direct-write platform enabling one- and two-photon absorption lithography, also in combination on one and the same sample. In the following, we describe both methods and show that both lead to excellent structural quality of surface micro-relief structures. As a showcase of what the system can do in principle, we designed and fabricated free-form micro-optical elements to project light from an LED as a defined light pattern onto a wall. The proper optical functionality of the fabricated element was shown within a demonstrator setup.

2.
Opt Express ; 26(6): A227-A239, 2018 Mar 19.
Article in English | MEDLINE | ID: mdl-29609333

ABSTRACT

Ultrashort pulse laser systems enable new approaches of material processing and manufacturing with enhanced precision and productivity. Time- and cost-effectiveness in the context of the industrialization of ultrashort laser pulse processes require an improvement of processing speed, which is of key importance for strengthening industrial photonics based manufacturing and extending its field of applications. This article presents results on improving the speed of a laser process by parallelization for creating light deflecting volume optics. Diffractive optical elements are fabricated directly inside the encapsulant of solar modules by utilizing a spatial light modulator based parallel laser microfabrication method. The fabricated volume optical elements effectively deflect light away from front side electrodes and significantly reduce the corresponding optical losses.

3.
Analyst ; 138(20): 5875-8, 2013 Oct 21.
Article in English | MEDLINE | ID: mdl-23964354

ABSTRACT

A novel optical sensor device monolithically integrated on a glass capillary is presented. Therefore, we took advantage of the ability to fabricate organic optoelectronic devices on non-planar substrates. The functionality of the concept is demonstrated by realizing an integrated oxygen sensor based on luminescence decay time measurement.


Subject(s)
Biosensing Techniques/methods , Capillary Action , Capillary Tubing , Luminescent Measurements/methods , Oxygen/analysis , Biosensing Techniques/instrumentation , Electrodes , Glass , Luminescent Measurements/instrumentation , Optical Devices
4.
Anal Bioanal Chem ; 405(18): 5975-82, 2013 Jul.
Article in English | MEDLINE | ID: mdl-23632883

ABSTRACT

The use of organic photodiodes (OPDs) for measuring phosphorescent lifetimes of optochemical oxygen sensors is described. Phosphorescent indicators with lifetimes ranging from ∼5 to 60 µs have been studied using light-emitting diodes as the excitation source and organic photodiodes integrated into the sensor substrate for detection. A measurement system using an adjusted electronic circuitry to detect photocurrents in the nanoampere range is presented. The response behaviour of the organic photodiodes has been characterized, and it was found that a forward (positive) bias had to be applied in order to decrease the response time of the OPDs to a range suitable for phosphorescence decay time measurements. A modulation cutoff frequency of ∼100 kHz has been determined, corresponding to a response time of the organic photodiodes of 1.6 µs. Two sensor dyes have been characterized regarding their lifetimes upon exposure to 0-20% oxygen, and it was shown that results comparable to literature data and inorganic photodetectors can be achieved.


Subject(s)
Luminescent Measurements/instrumentation , Luminescent Measurements/methods , Coloring Agents/analysis , Electronics , Equipment Design , Oxygen/analysis
5.
ACS Appl Mater Interfaces ; 4(10): 5608-12, 2012 Oct 24.
Article in English | MEDLINE | ID: mdl-23027799

ABSTRACT

This study shows that the morphology of organic/metal interfaces strongly depends on process parameters and the involved materials. The interface between organic n-type blocking layer materials and the top Ag cathode within an organic photodiode was investigated. Ag was deposited on either amorphous tris-8-hydroxyquinolinato-aluminum (Alq(3)) or crystalline 4,7-diphenyl-1,10-phenanthroline (Bphen) using different deposition techniques such as electron beam deposition, ion beam sputtering, and vacuum thermal evaporation at various deposition rates. The interfaces were studied by transmission electron microscopy and X-ray reflectivity. It was found that Bphen does not show any Ag diffusion no matter which deposition technique was used, whereas the Ag diffusion into Alq(3) depends on the deposition technique and the deposition rate. The highest amount of Ag diffusion into Alq(3) occurred by using thermal vacuum deposition at low deposition rates.

6.
Anal Bioanal Chem ; 404(10): 2841-9, 2012 Dec.
Article in English | MEDLINE | ID: mdl-22706404

ABSTRACT

An optical waveguiding sensor array featuring monolithically integrated organic photodiodes as integrated photo-detector, which simplifies the readout system by minimizing the required parts, is presented. The necessity of any optical filters becomes redundant due to the proposed platform geometry, which discriminates between excitation light and sensing signal. The sensor array is capable of measuring luminescence or absorption, and both sensing geometries are based on the identical substrate. It is demonstrated that background light is virtually non-existent. All sensing and waveguide layers, as well as in- and out-coupling elements are assembled by conventional screen-printing techniques. Organic photodiodes are integrated by layer-by-layer vacuum deposition onto glass or common polymer foils. The universal and simple applicability of this sensor chip is demonstrated by sensing schemes for four different analytes. Relative humidity, oxygen, and carbon dioxide are measured in gas phase using luminescence-based sensor schemes; the latter two analytes are also measured by absorbance-based sensor schemes. Furthermore, oxygen and pH in aqueous media were enabled. The consistency of calibration characteristics extending over different sensor chips is verified.

7.
Analyst ; 134(8): 1544-7, 2009 Aug.
Article in English | MEDLINE | ID: mdl-20448918

ABSTRACT

An optical sensor concept utilizing the sensing layer as the light propagating layer and a new method to couple light into a planar waveguide is presented. The concept enables simple manufacturing by coating or printing techniques and the integration of organic (plastic) opto-electronic components.

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