Abstract
This thesis presents the development of two complementary experimental platforms for quantum technology research: a direct laser writing system for material deposition and a scanning diamond probe microscope for nanoscale quantum sensing.
For the first platform, Conventional material deposition techniques such as photolithography involving chemical vapor deposition, physical vapor deposition and electroplating require complex procedures and demanding equipment. Additive manufacturing methods like stereolithography, selective laser sintering or inkjet printing offer single-step deposition but suffer from poor spatial resolution and limited material and substrate choices. We sought a single-step deposition mechanism applicable to common materials without com-promising mechanical strength or electrical conductance. We developed a laser-induced method combining photoinduced chemical reduction with optical trapping, experimentally realized by mixing a metallate solution with a semiconductor nanoparticle suspension. The mechanism works for various transition metals on different substrates. Our laser writing setup produces complex patterned depositions with high spatial resolution. The deposited structures show promising electrical and mechanical properties, and we can optically characterize the process in situ. We have verified the mechanism, characterized its performance, and demonstrated its application by fabricating several devices.
For the second platform, imaging physical quantities such as magnetic field, electric field and temperature with high spatial resolution near sample surfaces can reveal material interactions and dynamics. The nitrogen-vacancy center in diamond has been developed as an atomic-scale quantum sensor, but its spatial resolution remains underutilized. We aimed to build an NV-based scanning probe microscope for high-resolution imaging of physical quantities. We designed the mechanical and electronic modules, calibrated the galvo scanner, piezo tube and piezo stepper motor, characterized setup vibrations using a Michelson interferometer, and calibrated the tuning fork oscillation amplitude. The current system can simultaneously image sample topography and perform optical readout from NV centers, though we have not yet obtained a meaningful image of a typical sample. We have completed the preliminary design. Future improvements include enhancing mechanical stability and the signal-to-noise ratio of the tuning fork signal, and adding more imaging protocols.
Together, these two platforms represent a complete toolkit for quantum technology re-search: the ability to fabricate functional microstructures and the capability to characterize nanoscale phenomena with quantum sensors.