The proposal of magnetic resonance force microscopy (MRFM) and its subsequent realization combine the physics of magnetic resonance imaging (MRI) with the techniques of scanning probe microscopy. Driven by the ultimate goal of imaging a single nuclear spin and the promise of a molecular structure microscope, such work is being pursued in a handful of laboratories world-wide.
The synthesis and investigation of ferromagnetic nanostructures has been motivated both by a large number of potential applications and by fundamental questions about the physics of nanometer-scale magnetism. Magnetic nanoparticles have potential biological and biomedical applications, applications in high-resolution magnetic imaging, as magnetic sensors, and as dense magnetic storage media.
The coupling of mechanical modes to quantized electronic states represents an active area of research, in which various groups have observed nanomechanical effects in mesoscopic transport devices, most notably in suspended nanotube and nanowire (NW) transistors. Coupling of nanomechanical resonators to controllable quantum systems such as quantum dots (QDs) and superconducting qubits is in its early stages.
We are developing an easy-to-operate single photon source on a sharp tip at the end of an optical fiber. Our approach provides a practical solution for maximizing light extraction and could be applied to a variety of quantum systems, including semiconductor quantum dots or emitters in diamond. Potential also exists for applications as a scanning probe sensor.
Bottom-up nanowires are extremely promising as sensitive mechanical transducers. We have integrated such nanowire force sensorsinto a low-temperature scanning probe apparatus. Our ability to scan such force sensors is now opening are variety of scanning force measurements including measurements of weak lateral forces, atomic-scale friction, and vectorial force sensing.
We couple electromagnetic cavities to nanowire mechanical resonators via two approaches: On the one hand, we work on integrating a nanowire mechanical resonator with embedded quantum two-level system in an optical cavity. On the other hand, we couple a nanowire scanning probe to superconducting microwave cavities.