1. SAMWEL MAKUBI EMMANUEL
Electrical Engineering
Laboratory for Nanoscale Optics
Abstract:
Electroplating on Diamond for Reliable Microwave Delivery to Nanomechanical Devices
Point defects in diamonds have emerged as a remarkable material property for nanoscale photonics and
quantum optics. Nitrogen-vacancy (NV) color center is one of the many point defects in diamonds. The
NV center is comprised of a pair of a lattice vacancy and a neighboring nitrogen atom, which substitutes a
carbon atom. NV centers are room-temperature sources of single photons whose spin state can be
optically read-out. Additionally, their spins can be manipulated at room temperature by applying
Microwave radiation whose frequency matches the energy difference between its lower energy spin
states. The ease of manipulating spin states of NV centers in diamonds at room temperature makes them
an excellent candidate for a range of applications, such as fabrication of nanophotonic devices with NV
centers for room temperature quantum cryptography, quantum information processing, and biocompatible
devices for photonics-based chemical sensing schemes. Development in this field could potentially allow
for things like super high-resolution MRI and faster,more powerful (quantum) computers.
My work focuses on the application of Microwave on the CVD diamond sample to manipulate the spin
states of the NV centers,in hope to allow realized robust systems to deliver large Magnetic Field at a
specific site with the desired frequency. The ultimate goal of this research is to design and fabricate a
planar transmission line preferably spiral inductors or meandering structures on a 4mm x 4mm Diamond
substrate using electroplating to improve the inductance and current flowing through them, which would
lead to enhanced magnetic field delivery. Target frequency of the Microwave is at 2.87 GHz, which
matches the zero field splitting between spin |0⟩ and |±1⟩ of the ground state.
Designing transmission lines, involves the use of Finite Element Method (FEM). For this I used,
COMSOL Multiphysics to design the optimal structure for efficiently delivering Microwave on the
Diamond chip. Established design is implemented with the combination of photolithography for
patterning a seed layer, followed by electroplating for a thicker wire.