Optical Planar Waveguide Sensor with Integrated Digitally-Printed Light Coupling-in and Readout Elements

Abstract

Optical planar waveguide sensors, able to detect and process information from the environment in a fast, cost-effective, and remote fashion, are of great interest currently in different application areas including security, metrology, automotive, aerospace, consumer electronics, energy, environment, or health. Integration of networks of these systems together with other optical elements, such as light sources, readout, or detection systems, in a planar waveguide geometry is greatly demanded towards more compact, portable, and versatile sensing platforms. Herein, we report an optical temperature sensor with a planar waveguide architecture integrating inkjet-printed luminescent light coupling-in and readout elements with matched emission and excitation. The first luminescent element, when illuminated with light in its absorption band, emits light that is partially coupled into the propagation modes of the planar waveguide. Remote excitation of this element can be performed without the need for special alignment of the light source. A thermoresponsive liquid crystal-based film regulates the amount of light coupled out from the planar waveguide at the sensing location. The second luminescent element partly absorbs the waveguided light that reaches its location and emits at longer wavelengths, serving as a temperature readout element through luminescence intensity measurements. Overall, the ability of inkjet technology to digitally print luminescent elements demonstrates great potential for the integration and miniaturization of light coupling-in and readout elements in optical planar waveguide sensing platforms.

Thermochromic photoluminescent 3D printed polymeric devices based on copper-iodide clusters

“…Polymeric photoluminescent waveguides (PWGs) are nowadays used in a broad range of applications, such as in light-emitting devices (LEDs) [1], light-tunable photonics [2,3], optics [4], photonic integrated circuits [5], communications [6], biomedicals [7,8] and even sensors [9][10][11][12]. The possibility to exploit the thermal and mechanical stability of the polymeric matrices, joined to the flexibility of the final device and the inexpensiveness of the materials, has promoted the use of polymers as materials for innovative waveguides [10] but still a lot can be done, especially in the fabrication complex devices.…”

Facile fabrication of microlenses with controlled geometrical characteristics by inkjet printing on nanostructured surfaces prepared by combustion chemical vapour deposition

“…So, once ejected and deposited on the substrate, fixation to the substrate can be directly done by UV photopolymerization without the need of intermediate evaporation steps that complicate the lens preparation process and can lead to undesired geometry changes of the deposited features. By curing the deposited ink under mild vacuum conditions (100 mBar) solid printed elements, including waveguides, can be obtained with a refractive index of 1.56 and with optical losses of 0.5-0.6 dB/cm, as we have previously reported [37,39,40].…”

3D Printed Biohybrid Microsystems

“…The possibilities offered by the multiphoton lithography method are most clearly manifested in the highly promising and rapidly developing research line implying the fabrication of optical sensor systems based on fiber-optic structures. [210][211][212] The advantages of such sensors include their high sensitivity, small size, and the ability to fabricate integrated microfluidic systems.…”