Maskless manufacturing of quantum photonics components using focused ion beam

Abstract

This thesis advances quantum nanophotonics by integrating theoretical design, numerical
simulation, and focused ion beam (FIB) prototyping across distinct research efforts
operating at different wavelength regimes and material platforms. The Tamm plasmon
project investigated distributed Bragg reflector–based heterostructures supporting novel
Tamm plasmon modes, fabricated via FIB milling and metallisation, with prospects
for compact and tunable plasmonic lasers incorporating quantum wells. In parallel,
the diamond project developed two-dimensional photonic crystal membranes to control
emission from nitrogen-vacancy centers, focusing on Purcell suppression near photonic
band edges while addressing fabrication challenges. Nanohole arrays were patterned with
high precision using FIB, underscoring the critical influence of ion species choice and
milling parameters on device quality.
This work employed both liquid metal ion source (LMIS) and plasma FIB (pFIB)
systems. LMIS, based on gallium ions, provides high-resolution patterning, whereas pFIB
enables faster milling with inert gas ions such as argon, thereby reducing contamination
and broadening the accessible processing window. The use of FIB significantly shortens
the feedback loop between simulation, fabrication, and characterization relative to
conventional foundry-based approaches, allowing rapid iterative prototyping of nanoscale
photonic devices. This establishes FIB as a powerful platform bridging simulation and
experiment, supporting future innovation in integrated quantum photonics.

Date of Award	9 Dec 2025
Original language	English
Awarding Institution	University of Bristol
Supervisor	Alex S Clark (Supervisor) & Edmund G H Harbord (Supervisor)