Proc. SPIE. 10249, Integrated Photonics: Materials, Devices, and Applications IV
KEYWORDS: Lithography, Photonic devices, Mirrors, Two photon polymerization, Resonators, Waveguides, Optical properties, Polymers, Single mode fibers, Scanning electron microscopy, Photoresist materials, 3D metrology, Sensing systems
In this paper we demonstrate design and fabrication of two- (2D) and three-dimensional (3D) ring resonators prepared by 3D laser lithography based on two photon polymerization. We used dip-in direct-laser-writing (DLW) optical lithography to fabricate 3D optical structures for optics and optoelectronics. Prepared structures are embedded in polydimethylsiloxane, which is well known silicon elastomer with unique mechanical and optical properties. This polymer structure allows to couple light directly from single mode optical fiber to the ring resonator structure, where polydimethylsiloxane creates cladding. Optical properties of prepared 2D and 3D ring resonators were investigated by measurement of transmission spectral characteristics.
Progress in nanotechnologies accelerated the polymer based photonics, where simple and cheap solutions often bring comparable and sometimes also novel interesting results. Good candidates are polymer photoresists and siloxane materials with unique mechanical and optical properties. We present laser lithography as efficient tool for fabrication of different three-dimensional (3D) structures embedded in polydimethylsiloxane (PDMS) membranes. Presented concept of PDMS based thin membranes with 3D structures works as an effective diffraction element for modification of radiation pattern diagram of light emitting diodes and changes also the angular photoresponse of photodiodes. All these results were demonstrated on two types of 3D structures – spheres arranged in cubic lattice and woodpile structure.
In this contribution, we present modification of far field of light emitting diode (LED) with implemented Fresnel structure in the LED surface. Fresnel structures were prepared in one-dimensional arrangement with two different foci f1 = 12.5 μm and f2 = 1 cm. Structures were etched directly in the LED emitting surface using electron beam lithography with the etched depth for the structure with f1 and f2 app. 200 nm and 400 nm, respectively. Due to application of these structures, LED far field narrowing was observed, which is documented by goniophotometer measurements. For the structure with f1 and f2, the intensity decrease for angles ±30° – ±50° is app. 3-4% and 5-6%, respectively, in comparison to the Lambertian profile.
In this paper, the fabrication method of waveguide structures and devices as ring resonators for different waveguide applications based on polymer material is presented. The structures were designed in computer-aided design (CAD) software and two-photon polymerization lithography system was used for preparation of desired devices. Morphological properties of prepared devices were investigated using scanning electron microscope (SEM) and confocal microscope. Finally, we performed measurement of optical spectrum characteristics in telecommunication wavelengths range. The results corresponds to calculated parameters. Final polymer devices are promising for lab on a chip and sensing applications due to unique elastic and chemical properties.
This contribution presents implementation of one dimensional Fresnel structure in surface emitting part of the AlGaAs/GaAs multi-quantum well light emitting diode (LED).The structure consists in drilled lines distributed with square root of distance in order to obtain structures with different foci. First structure was prepared by electron beam lithography and etched directly in the emitting surface using reactive-ion etching. Second structure was prepared in the surface of thin PDMS membrane that can be stack directly on the emitting surface. The membrane is fabricated using dip in laser lithography combined with PDMS embossing. Implementation of such Fresnel structures leads in modification of LED far-field what was proved by goniophotometer measurements.
Polymer based photonics brings simple and cheap solutions often with interesting results. We present capabilities of some siloxanes focusing on polydimethylsiloxane (PDMS) with unique mechanical and optical properties. In combination of laser lithography technologies with siloxane embossing we fabricate different grating structures with one- and two-dimensional symmetry. Concept of PDMS based thin membranes with patterned surface as an effective diffraction element for modification of radiation pattern diagram of light emitting diodes is here shown. Also the PDMS was used as an alternative material for fabrication of complicated waveguide with implemented Bragg grating. For lab-on-chip applications, we patterned PDMS microstructures for microfluidic and micro-optic devices.
In this paper we present preparation process of ring resonator in racetrack configuration based on polydimethylsiloxane (PDMS). 3D laser lithography in combination with imprinting technique was used to pattern photoresist layer as a master for imprinting process. In the next step, PDMS ring resonator was imprinted and filled with core PDMS. Finally, morphological properties of prepared device were investigated by scanning electron microscope (SEM) and confocal microscope and transmission spectrum measurements were performed.
In this paper we demonstrate possibilities of three-dimensional (3D) printing technology based on two photon polymerization. We used three-dimensional dip-in direct-laser-writing (DLW) optical lithography to fabricate 2D and 3D optical structures for optoelectronics and for optical sensing applications. DLW lithography allows us use a non conventional way how to couple light into the waveguide structure. We prepared ring resonator and we investigated its transmission spectral characteristic. We present 3D inverse opal structure from its design to printing and scanning electron microscope (SEM) imaging. Finally, SEM images of some prepared photonic crystal structures were performed.
Nowadays, lab on a chip (LOC) applications are very popular in the field of biomedicine. LOC device works with biological materials and enables to arrange conventional laboratory operations on a small chip. Philosophy of LOC applications stands on quick and precise diagnostics process and technology, which uses cheap materials with possibility of rapid prototyping. LOC, as a time saving application, works with small volume of samples and reagents and enables better control over the sample.
We present fabrication method of functional LOC chip for different biomedical microfluidic applications based on direct laser writing (DLW) lithography. We present fabrication of few types of microfluidic and micro-optic structures with different capabilities created by DLW system. The combination of DLW lithography in photoresist layer deposited on glass substrate and polydimethylsiloxane (PDMS) replica molding process were used for patterning of designed microstructures. Prepared microfluidic and micro-optic structures were observed by confocal microscope and microfluidic flow observations were investigated by conventional optical microscope and CCD camera.
We describe new technologies for a fabrication of microfluidics and micro-optics components for lab-on-a-chip applications based on polydimethylsiloxane. We use combination of direct laser writing (DLW) lithography for channel patterning in photoresist layer with PDMS imprinting process. Unique imprinting and optical properties favors PDMS for fabrication of different microchannels and microlens arrays. This technology allows the fabrication of different PDMS channel structures. Also PDMS based microlens arrays were patterned in photoresist layer by DLW process and also by interference lithography and imprinted in PDMS layer. Spontaneous microlens array based on polystyrene microspheres was also prepared by spin-coating of dispersed microspheres in photoresist and for organized microlens array we used predefined two-dimensional grid prepared by interference lithography. Final structures were investigated by confocal and optical microscope. The prepared PDMS and polystyrene based microdevices can be used in lab-on-a-chip applications in sensing and biological measurements.
In this paper we present results of an implementation of thin two-dimensional (2D) photonic crystal (PhC) patterned in thin polydimethylsiloxane (PDMS) membranes on the light emitting diode (LED) surface. PDMS membranes were patterned by using the interference lithography in combination with imprinting technique. 2D PhC surface relief structures of period 580 nm were patterned in thin PDMS membranes with depth up to 150 nm. Patterned PDMS membranes placed on different optoelectronic device surface could modify the final optical properties.
We describe fabrication process of optical waveguide structures such as multi-mode optical splitter and optical waveguide with surface Bragg grating in polydimethylsiloxane (PDMS). Technology based on drawing of thin photoresist fiber with diameter up to 100 μm was developed and optimized. In this way, fibers drawn from photoresist form cores of waveguides in PDMS slab. After removal of the photoresist, created air channels can be filled in with different liquids. We prepared multimode waveguide structures in PDMS composed of two PDMS materials with different refractive indices. Using this technology, also complicated waveguide structures were prepared as optical splitter and surface Bragg grating were prepared in PDMS material.
In this paper, capabilities of the fabrication technology for planar waveguide structures and devices in polydimethylsiloxane (PDMS) are presented. Direct laser writing in combination with imprinting technique was used to pattern photoresist layer as a master for imprinting process. In the next step, PDMS waveguide structures as channel waveguide, Y-branch waveguide splitter and ring resonator were imprinted. Finally, optical and morphological properties of prepared devices were investigated by confocal microscopy and atomic force microscopy.
The paper describes the preparation of polydimethylsiloxane (PDMS) fiber integrated on the conventional optical fibers and their use for optical fiber displacement sensor. PDMS fiber was made of silicone elastomer Sylgard 184 (Dow Corning) by drawing from partially cured silicone. Optical fiber displacement sensor using PDMS fiber is based on the measurement of the local minimum of optical signal in visible spectral range generated by intermodal interference of circularly symmetric modes. Position of the local minimum in spectral range varies by stretching the PDMS fiber of 230 μm in the wavelength range from 688 to 477 nm. In the stretched PDMS fiber is possible to determine the longitudinal displacement with an accuracy of approximately 1 micrometer.