3D-Printed Optics for Wafer-Scale Probing

Mass production of photonic integrated circuits requires high-throughput wafer-level testing. We demonstrate that optical probes equipped with 3D-printed elements allow for efficient coupling of light to etched facets of nanophotonic waveguides. The technique is widely applicable to different integration platforms.Comment: Accepted for presentation at European Conference on Optical Communications (ECOC) 201

3D-Printed Scanning-Probe Microscopes with Integrated Optical Actuation and Read-Out

Scanning‐probe microscopy (SPM) is the method of choice for high‐resolution imaging of surfaces in science and industry. However, SPM systems are still considered as rather complex and costly scientific instruments, realized by delicate combinations of microscopic cantilevers, nanoscopic tips, and macroscopic read‐out units that require high‐precision alignment prior to use. This study introduces a concept of ultra‐compact SPM engines that combine cantilevers, tips, and a wide variety of actuator and read‐out elements into one single monolithic structure. The devices are fabricated by multiphoton laser lithography as it is a particularly flexible and accurate additive nanofabrication technique. The resulting SPM engines are operated by optical actuation and read‐out without manual alignment of individual components. The viability of the concept is demonstrated in a series of experiments that range from atomic‐force microscopy engines offering atomic step height resolution, their operation in fluids, and to 3D printed scanning near‐field optical microscopy. The presented approach is amenable to wafer‐scale mass fabrication of SPM arrays and capable to unlock a wide range of novel applications that are inaccessible by current approaches to build SPMs

Superconducting Nanowire Single-Photon Detector (SNSPD) with 3D-Printed Free-Form Microlenses

We present an approach to increase the effective light-receiving area of superconducting nanowire single-photon detectors (SNSPD) by means of free-form microlenses that are printed in situ on top of the sensitive detector area using high-resolution multi-photon lithography. We demonstrate a detector based on a niobium-nitride (NbN) nanowire with a 4.5 $\mathrm \mu$m $\times$ 4.5 $\mathrm \mu$m sensitive area, supplemented with a lens of 60 $\mathrm \mu$m diameter. For free-space illumination at a wavelength of 1550 nm, the lensed sensor has a 100-fold-increased effective collection area, which leads to strongly enhanced system detection efficiency without the need for long nanowires. Our approach can be readily applied to a wide range of sensor types and effectively overcomes the inherent design conflict between high counting speed due to short sensor reset time, high timing accuracy, and high fabrication yield on the one hand and high collection efficiency through large effective detection areas on the other hand.Comment: 25 pages, 6 figure

Custom-Designed Glassy Carbon Tips for Atomic Force Microscopy

Glassy carbon is a graphenic form of elemental carbon obtained from pyrolysis of carbon-rich precursor polymers that can be patterned using various lithographic techniques. It is electrically and thermally conductive, mechanically strong, light, corrosion resistant and easy to functionalize. These properties render it very suitable for Carbon-microelectromechanical systems (Carbon-MEMS) and nanoelectromechanical systems (Carbon-NEMS) applications. Here we report on the fabrication and characterization of fully operational, microfabricated glassy carbon nano-tips for Atomic Force Microscopy (AFM). These tips are 3D-printed on to micro-machined silicon cantilevers by Two-Photon Polymerization (2PP) of acrylate-based photopolymers (commercially known as IP-series resists), followed by their carbonization employing controlled pyrolysis, which shrinks the patterned structure by ≥98% in volume. Tip performance and robustness during contact and dynamic AFM modes are validated by morphology and wear tests. The design and pyrolysis process optimization performed for this work indicate which parameters require special attention when IP-series polymers are used for the fabrication of Carbon-MEMS and NEMS. Microstructural characterization of the resulting material confirms that it features a frozen percolated network of graphene sheets accompanied by disordered carbon and voids, similar to typical glassy carbons. The presented facile fabrication method can be employed for obtaining a variety of 3D glassy carbon nanostructures starting from the stereolithographic designs provided by the user