ABSTRACT
In this article we demonstrate rapid manufacturing of an illumination quality double-sided centimeter-scale optics without any post-processing. Two methods are presented: additive manufacturing (AM) using an optically transparent material with a water-soluble support material (support method), and alternatively, using only the optically transparent material but flipping the optics mid-process (flipping method). The main advantage of the flipping method is that only one material is needed. However, the use of support material is more straightforward, allows better alignment between the two sides of the lens and enables more complex lenses manufactured in the future. Both methods result in sufficient surface quality, i.e. surface roughness Rq = 11.48 ±3.32 nm and form accuracy of ±10 µm, for the purposes of illumination optics.
ABSTRACT
Three-dimensional (3D) printing of imaging-quality optics has been challenging due to the tight tolerances on surface shape and roughness. We report on manufacturing such optics with Print optical Technology, which is based on modified ink-jet printing. We demonstrate for the first time a 3D-printed singlet lens with a surface profile deviation of ±500 nm within a 12-mm aperture diameter. Its RMS surface roughness is below 1 nm without surface polishing. The printed lens exhibits an imaging resolution of some 140 lp mm -1 at 100-mm focal length in the visible region.
ABSTRACT
The responses of a polymer ridge waveguide Young interferometer with and without a bilayer of Al2O3/TiO2, fabricated by atomic layer deposition, are studied and compared when applied as an aqueous chemical sensor. The phase shift of the guided mode, as a result of the change in refractive index of the cover medium, is monitored. The results indicate that the over-coating affects the linearity of the sensor response. The effect of concentration on the linearity of the sensor response is investigated by applying different concentrations of water-ethanol solution. Although the performance of the sensor is improved by the additional layers, the study reveals a non-monotonic behavior of the device. We show that it comes mainly from the adsorption of ethanol molecules on the surface of the films. Such an understanding of the platform is crucial for sensing of analytes involving polar molecules.
ABSTRACT
We present a convenient, low-cost, and mass-production-compatible technique for the fabrication of strip-loaded waveguides. The technique is based on the atomic layer deposition of a slab waveguide, nanoimprinting of a strip, and integration of two structures by lamination. The guiding layer is chosen to be a 200 nm thick titanium dioxide film. The waveguide characteristics are determined by the use of ring resonators. The technique is demonstrated for titanium dioxide thin films, but it is applicable to any other material that meets the refractive index difference condition between the loading strip and the slab waveguide.
ABSTRACT
We demonstrate a polymer slot waveguide Young interferometer coated with a bilayer of Al2O3/TiO2. The approach enables relaxed dimensions of the polymer waveguide which simplifies the fabrication of the structure with a resolution of 50 nm. The layers were coated by an atomic layer deposition technique. The feasibility of the device was investigated by exploiting the interferometric structure as a bulk refractive index sensor operating at 975 nm wavelength for detection of an ethanol-water solution. A refractive index change of 1 × 10-6 RIU with a sensing length of only 800 µm was detected. The approach confirms the possibility of realizing a low cost device with a small footprint and enhanced sensitivity by employing the TiO2 rails in the sides of the slot waveguide.
ABSTRACT
The refractive index sensitivity of a polymer slot waveguide coated with a bilayer of Al2O3/TiO2 was investigated theoretically and optimized for biosensor applications. The influence of atomic-layer-deposition-coated thin high-refractive-index layers on the slot confinement factor and the homogeneous sensitivity of polymer slot waveguides with different geometries were simulated. The results were compared with those of an optimized noncoated polymer slot waveguide, both operating at visible wavelengths. The simulations reveal that the proposed structure offers a significant improvement in the confinement factor and the sensitivity. These calculations present guidelines for the design and fabrication of relatively sensitive polymer slot waveguide devices for low-cost biochemical sensor applications.
