Organic-based microcavities with vibronic progressions: Linear spectroscopy

In this work we study from a theoretical point of view microcavities embedding organic materials featuring vibronic progressions. As already shown in seminal experiments, the presence of vibronic replicas largely enriches the physics of such systems with the appearance of new polariton dispersion branches. We calculate the linear optical properties of such microcavities using two distinct models, quantum the first, macroscopic the latter, which are fully consistent with each another. They are shown to describe the strong-coupling regime in very good agreement with the available experimental data, using independently determined material parameters.

Figure 1

Sketch of the system geometry: an organic resonant material of length $L_a$, with dipole moment $\mathit{\mu }$, is embedded in a microcavity. The optical properties of such a system are investigated with reflectivity experiments.

Figure 2

Simulated absorption spectrum of a hypothetical bare 260-nm-thick film.

Figure 3

Reflectivity $s$-polarized spectra with $s$-polarized incident light of the material embedded in a high-quality microcavity. This simulation has been performed with the microscopic model.

Figure 4

Transmissivity $p$-polarized spectra with $s$-polarized incident light of the material embedded in a high-quality microcavity. This simulation has been performed with the microscopic model.

Figure 5

Absorbtion spectra with $s$-polarized incident light of the material embedded in a high-quality microcavity. This simulation has been performed with the macroscopic model.

Figure 6

Transmissivity $p$-polarized spectra with $s$-polarized incident light of the material embedded in a high-quality microcavity. This simulation has been performed with the macroscopic model.

Figure 7

(a) Simulated absorbance of a bare 50-nm-thick NTCDA slab. In the inset the experimental spectrum adapted from Ref. 9. (b) Experimental setup reproduced in the simulations.

Figure 8

Theoretical (upper) and experimental (lower), adapted from Ref. 9, reflectivity spectra for a 60-nm-thick slab of NTCDA in microcavity, obtained with $p$-polarized incident light. Spectra are plotted with an angular step of $8°$ and they are shifted for clarity.

Figure 9

(Color online) Reflectivity spectra (linear color scale) vs angle and energy. These plot show the dispersion relations obtained from reflectivity spectra for the 40-nm-thick (left) and 60-nm-thick (right) NTCDA slabs. Theoretical dispersion curves are the minima of darker areas pointed by arrows while experimental ones are shown as spots. At lower and higher energies are evident DBR sidebands.