Opto-PCB: Three demonstrators for optical interconnections

We report on a research project targeting optical waveguide integrated PCBs conducted within the European FP6 Network of Excellence on Micro-Optics NEMO. For three identified feature requests we have built three specific demonstrators respectively addressing the integration of active components, the fabrication of peripheral fibre ribbons and the integration of multiple layers of waveguides on the board

Correlation optics in progress: introduction to the feature issue

This feature issue of Applied Optics contains a series of selected papers reflecting recent progress of correlation optics and showing, in part, the trend from micro-optics to nano-optics

Bidimensional planar micro-optics for optochemical absorbance sensing

A new approach for developing optochemical absorbance sensors is presented. The method is based on a planar micro-optic circuit in which an optochemically active membrane that responds to selective compounds is deposited in the device, yielding a part of the guiding planar structure. In this way the optical field is confined in the direction transverse to the substrate and controlled in the lateral direction by means of planar micro-optics components. High sensitivity of the device can be easily obtained because of the relatively long light paths through the membrane, and the response time is low because the analyte has to diffuse through a several-micrometer-thin membrane. Experimental results of measurements of the concentration of potassium are also presented to verify the possibilities of these devices as specific absorbance sensors

Multimode interference devices for focusing in microfluidic channels

Low-cost, compact, automated optical microsystems for chemical analysis, such as microflow cytometers for identification of individual biological cells, require monolithically integrated microlenses for focusing in microfluidic channels, to enable high-resolution scattering and fluorescence measurements. The multimode interference device (MMI), which makes use of self-imaging in multimode waveguides, is shown to be a simple and effective alternative to the microlens for microflow cytometry. The MMIs have been designed, realized, and integrated with microfluidic channels in a silica-based glass waveguide material system. Focal spot sizes of 2.4 µm for MMIs have been measured at foci as far as 43.7 µm into the microfluidic channel

Design rules for combined label-free and fluorescence Bloch surface wave biosensors

We report on the fabrication and physical characterization of optical biosensors implementing simultaneous label-free and fluorescence detection and taking advantage of the excitation of Bloch surface waves at a photonic crystal’s truncation interface. Two types of purposely-designed one dimensional photonic crystals on molded organic substrates with micro-optics were fabricated. These feature either high or low finesse of the Bloch surface wave resonances and were tested on the same optical readout system. The experimental results show that designing biochips with a large resonance quality factor does not necessarily lead in the real case to an improvement of the biosensor performance. Conditions for optimal biochips’ design and operation of the complete bio-sensing platform are established

Focusing and imaging with increased numerical apertures through multimode fibers with micro-fabricated optics

The use of individual multimode optical fibers in endoscopy applications has the potential to provide highly miniaturized and noninvasive probes for microscopy and optical micromanipulation. A few different strategies have been proposed recently, but they all suffer from intrinsically low resolution related to the low numerical aperture of multimode fibers. Here, we show that two-photon polymerization allows for direct fabrication of micro-optics components on the fiber end, resulting in an increase of the numerical aperture to a value that is close to 1. Coupling light into the fiber through a spatial light modulator, we were able to optically scan a submicrometer spot (300 nm FWHM) over an extended region, facing the opposite fiber end. Fluorescence imaging with improved resolution is also demonstrated.Comment: 5 pages, 3 figure

Microfluidics for Energy Applications

This paper was presented at the 4th Micro and Nano Flows Conference (MNF2014), which was held at University College, London, UK. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute, ASME Press, LCN London Centre for Nanotechnology, UCL University College London, UCL Engineering, the International NanoScience Community, www.nanopaprika.eu.Microfluidic methods developed primarily for medical applications have much to offer energy applications. This short paper will provide the motivation and outline my group’s recent work in two such areas: (1) microfluidics and optics for bioenergy and (2) microfluidics for carbon management. Full details will be provided in talk. Within the bioenergy theme, we are developing photobioreactor architectures that leverage micro-optics and microfluidics to cater both light and fluids to maximize productivity of microalgae. Within the carbon management theme we are developing a suite of methods to study porescale transport and reactivity in carbon sequestration and enhanced oil recovery. Results indicate potential for order of magnitude gains in photobioreactor technology and a 100-fold improvement over current subsurface fluid transport analysis methods

What did the students expect from TPU and what they have got: comparative study

Backlight units are the most relevant element in display with respect to the energy consumption. In addition, the quality of backlight units in terms of brightness, homogenous light distribution, and the angle of light radiation, dramatically influence the overall quality of a display. Within this paper a new approach for the production of complex micro optics on large surfaces is presented. The technology is being optimised within the FlexPAET project for the production of next generation backlight units which allow for more efficient display illumination