In the first part of the presentation, I will reflect on the latest achievements regarding the development of the theoretical formalism that describes the interaction of photons and electronic excitations in layered van der Waals crystals [1].  In the following I will talk about the results of that formalism which relate to; 1. the excitons intensity vs doping in black phosphorus [1]; 2. the interaction between cavity photons and excitons in transition-metal dichalcogenides (TMDs) and in fullerene (C₆₀) thin films [2,3] and; 3. the interaction between  ‘free’  s(TE) photons and excitons  (formation of trapped photons) in  WS₂/hBN and in C₆₀  multilayers [4,5]. Finally, I will show the advantages and disadvantages of the current research and in which direction the research will continue. 

The spectral intensity of the s(TE) cavity photon n=1 in the (a) empty Al/Al₂O₃/vacuum/Al cavity (N = 0)  and in the cavity supporting C₆₀ film of thicknesses (b) N = 5,  and (c) N = 25 molecular layers. Here, ω_ex1, ω_ex2  and ω_ex3 denote three of the most intensive π-excitons in C₆₀.

[1] D. Novko, K. Lyon, D. J. Mowbray, and V. Despoja Phys. Rev. B 104, 115421 (2021)

[2] D. Novko and V. Despoja, Phys. Rev. Research 3, L032056 (2021)

[3] V. Despoja and D. Novko, Phys. Rev. B 106, 205401 (2022)

[4] V. Despoja and L. Marušić, Int. J. Mol. Sci. 23, 6943  (2022)

[5] N. Golenić and V. Despoja, Phys. Rev. B Lett., under review