Multifunctional lab in fiber technology seeks to translate the accomplishments of optofluidic, lab on chip devices into silica fibers. a robust, flexible, and ubiquitous optical communication platform that can underpin the ‘Internet of Things’ with distributed sensors, or enable lab on chip functions deep inside our bodies. Femtosecond lasers have driven significant advances in three-dimensional processing, enabling optical circuits, microfluidics, and micro-mechanical structures to be formed around the core of the fiber. However, such processing typically requires the stripping and recoating of the polymer buffer or jacket, increasing processing time and mechanically weakening the device. This paper reports on a comprehensive assessment of laser damage in urethane-acrylate-coated fiber. The results show a sufficient processing window is available for femtosecond laser processing of the fiber without damaging the polymer jacket. The fiber core, cladding, and buffer could be simultaneously processed without removal of the buffer jacket. Three-dimensional lab in fiber devices were successfully fabricated by distortion-free immersionlens focusing, presenting fiber-cladding optical circuits and progress towards chemically-etched channels, microfluidic cavities, and MEMS structure inside buffer-coated fiber.
We report progress in the development of a new technique that has the potential to enable the vacuum deposition of OLEDs with feature sizes ≤ 20um, and hence high resolution OLED displays. An OLED device with 16um by 130um sub-pixel size has been successfully demonstrated utilizing the novel idea of the in-situ shadow mask patterning method showing the capability to achieve high resolution OLED patterning. In the approach proposed here, two sheets of polyimide film are mounted on the bottom electrode of an OLED. The top sheet of the two stacked sheets is patterned insitu by laser ablation to create apertures to function as a deposition shadow mask. The lower sheet, which serve as a protective layer to the electrode during the laser ablation step is then removed, and OLED materials are deposited through the now patterned top sheet. Since mask alignment is not required in this approach, the technique circumvents the resolution limitations imposed by the difficulty of aligning shadow masks in the conventional techniques, and allows achieving high resolution pixel patterning. Furthermore, shadow effects, another factor that limits resolution in conventional techniques, can be reduced due to the use of very thin polyimide film (~7.5um) that is directly held on the substrate by electrostatic force. In principle, by applying this technique to the standard three color side-by-side sub-pixel matrix scheme, a resolution and aperture ratio of 338ppi and 60%, respectively, can be expected, which is estimated based on the fact that the width of the deposited material is 25um for the 16um wide electrode.