PR35 Photon Pairs Generated by PRBS Pumping of Silicon Photonic Micro-resonators (1640968-Y2)

Our sub-project focused on the development of key building blocks for microchips that are cost-effective, leverages modern micro-fabrication platforms, reduces operational complexity and improves scalability. Summary of a Project Outcomes report of research funded by the U.S. National Science Foundation under Project Number 1640968 (Year 2).

PR_34 Improved Photon-Pair Generation using Silicon Photonic Micro-resonators (1640968-Y1)

We focus on the development of key building blocks for entangled photon-pair generation using microchips that are cost-effective, compact, energy efficient and leverages modern micro-fabrication platforms such as silicon photonics. Summary of a Project Outcomes report of research funded by the U.S. National Science Foundation under Project Number 1640968 (Year 1).

PR38 Progress Towards Integrated Photon-Pair Sources and Their Applications (1640968-Y5)

The objective of this project was to make significant advances in quantum optical communications through the design, fabrication and demonstration of novel devices at the microchip scale. The principal goal of the device sub-project was to develop key building blocks for photonic microchips that are energy-efficient, leverages modern micro-fabrication platforms, reduces operational complexity and improve scalability with the potential for future adoption by industry. Summary of a Project Outcomes report of research funded by the U.S. National Science Foundation under Project Number 1640968 (Year 5).

Fabrication of lithium niobate fork grating by laser-writing-induced selective chemical etching

We propose and experimentally demonstrate a laser-writing-induced selective chemical etching (LWISCE) technique for effective micro-fabrication of lithium niobate (LN) crystal. Laser writing of LN crystal produces negative domains and domain walls. Also, it causes local lattice defects, in which the etching rates are significantly increased in comparison to the original LN crystal. In experiment, we use the LWISCE technique to fabricate various fork gratings in an X-cut LN crystal for the generation of vortex beams. In comparison to etching an untreated X-cut LN crystal, the etching rates of the laser-writing-induced boundaries and the central laser-irradiated areas are enhanced by a factor of 26 and 16, respectively. The width and depth of fork grating structure can be precisely controlled by laser writing parameters. Our method provides an efficient mask-free micro-fabrication technique for LN crystal, which can be readily applied to other ferroelectric crystals such as lithium tantalate, potassium titanyl phosphate and barium calcium titanate.

Enhanced Energy Harvesting of Flexural Waves in Elastic Beams by Bending Mode of Graded Resonators

We show efficient elastic energy transfer and wave confinement through a graded array of resonators attached to an elastic beam. Experiments demonstrate that flexural resonators of increasing lengths allow to reduce wave scattering and to achieve the rainbow effect with local wavefield amplifications. We show that the definition of a monotonically decreasing distribution of the natural frequencies of the resonators along the wave propagation direction, is the preferable choice to increase the energy efficiency of the system. The proposed configuration is suitable for micro-fabrication, envisaging practical applications for micro-scale vibration energy harvesting.

DNA Studies: Latest Spectroscopic and Structural Approaches

This review looks at the different approaches, techniques, and materials devoted to DNA studies. In the past few decades, DNA nanotechnology, micro-fabrication, imaging, and spectroscopies have been tailored and combined for a broad range of medical-oriented applications. The continuous advancements in miniaturization of the devices, as well as the continuous need to study biological material structures and interactions, down to single molecules, have increase the interdisciplinarity of emerging technologies. In the following paragraphs, we will focus on recent sensing approaches, with a particular effort attributed to cutting-edge techniques for structural and mechanical studies of nucleic acids.

A Two-Axis Piezoresistive Force Sensing Tool for Microgripping

Force sensing has always been an important necessity in making decisions for manipulation. It becomes more appealing in the micro-scale context, especially where the surface forces become predominant. In addition, the deformations happening at the very local level are often coupled, and therefore providing multi-axis force sensing capabilities to microgripper becomes an important necessity. The manufacturing of a multi-axis instrumented microgripper comprises several levels of complexity, especially when it comes to the single wafer fabrication of a sensing and actuation mechanism. To address these requirements, in this work, an instrumented two-axis force sensing tool is proposed, which can then be integrated with the appropriate actuators for microgripping. Indeed, based on the task, the gripper design and shape requirements may differ. To cover wide needs, a versatile manufacturing strategy comprising of the separate fabrication of the passive and sensing parts was especially investigated. At the microscale, signal processing brings additional challenges, especially when we are dealing with multi-axis sensing. Therefore, a proper device, with efficient and appropriate systems and signal processing integration, is highly important. To keep these requirements in consideration, a dedicated clean-room based micro-fabrication of the devices and corresponding electronics to effectively process the signals are presented in this work. The fabricated sensing part can be assembled with wide varieties of passive parts to have different sensing tools as well as grippers. This force sensing tool is based upon the piezoresistive principle, and is experimentally demonstrated with a sensing capability up to 9 mN along the two axes with a resolution of 20 μN. The experimental results validate the measurement error within 1%. This work explains the system design, its working principle, FEM analysis, its fabrication and assembly, followed by the experimental validation of its performance. Moreover, the use of the proposed sensing tool for an instrumented gripper was also discussed and demonstrated with a micrograsping and release task.