Tamm modes are unique electromagnetic surface modes arising from the interface between a metal and a distributed Bragg reflector (DBR), exhibiting distinct dip in the reflectance spectrum within the photonic bandgap of the cavity. Tamm plasmon structures offer mode tunability through patterned metal layer, polarisation independence and ease of fabrication. These structures have been shown to improve the spontaneous emission of single photon sources , which is invaluable in quantum technologies. 

In this work, we investigate Tamm modes in the O-band using Lumerical FDTD. The Tamm structure consists of DBR of AlAs (110.4nm thick) and GaAs (94.2nm thick), with a spacer layer of GaAs (75nm thick) patterned with 120nm Au layer. Linear Au gratings of period 1350nm and thickness of 100nm are etched into the Au layer to explore their impact on the photonic bandgaps of the structure. Tailoring the bandgap of the structure enables precise control of light propagation within the structure, dispersion properties and engineer novel optical phenomena, unlocking new applications in photonics and quantum technologies. We extend this work by investigating the changes in dispersion properties with the addition of photonic crystal cavities, and bullseye microcavities.