This repository contains research data for all figures in the manuscript entitled ‘Optomechanical Pumping of Collective Molecular Vibrations in Plasmonic Nanocavities’. This includes experimental SERS data from NPoM nanocavities as well as optomechanical simulations. All data are provided in .txt files, space separated, with columns labelled in the first row. The data are organized in folders for each figure, with individual files for each figure panel containing data. Further information can be found in the figure captions of the manuscript.

Detailed information on figure data: Figure 1d: Simulation of the scattering cross section and near-field enhancement of a NPoM nanocavity. Experimentally measured scattering spectrum of a NPoM nanocavity. Figure 1e: Simulation of the self-interaction Green’s function G of a NPoM nanocavity in the centre of the molecular patch, both real and imaginary part. Figure 1f: Simulation of the optomechanical pumping (\Gamma_+) and damping (\Gamma_-) rate, as well as the combined optomechanical pumping rate (\Gamma_opt). Figure 2a: Power-normalised anti-Stokes spectra of BPT in NPoMs, excited with a pulsed laser (785 nm, 80 MHz, 0.5 ps) at powers 0.5, 1.0, 2.0, 5.0, 10 and 20 uW average power. Spectra are averaged over 70 NPoMs. Figure 2b: Power-normalised Stokes spectra of BPT in NPoMs, excited with a pulsed laser (785 nm, 80 MHz, 0.5 ps) at powers 0.5, 1.0, 2.0, 5.0, 10 and 20 uW average power. Spectra are averaged over 70 NPoMs. Figure 3a: Stokes and anti-Stokes signal extracted from SERS spectra vs in-coupling corrected laser intensity for the 292 cm^-1 vibrational mode. Separate data files contain experimental data of individual NPoMs, this experimental data averaged in laser intensity bins (binned), as well as optomechanical simulations. Figure 3b: Stokes and anti-Stokes signal extracted from SERS spectra vs in-coupling corrected laser intensity for the 1080 cm^-1 vibrational mode. Separate data files contain experimental data of individual NPoMs, this experimental data averaged in laser intensity bins (binned), as well as optomechanical simulations. Figure 3c: Stokes and anti-Stokes signal extracted from SERS spectra vs in-coupling corrected laser intensity for the 1586 cm^-1 vibrational mode. Separate data files contain experimental data of individual NPoMs, this experimental data averaged in laser intensity bins (binned), as well as optomechanical simulations. Figure 3d: Ratio of anti-Stokes to Stokes signal extracted from SERS spectra vs in-coupling corrected laser intensity for the 292 cm^-1 vibrational mode. Separate data files contain experimental data of individual NPoMs, this experimental data averaged in laser intensity bins (binned), as well as optomechanical simulations. Figure 3e: Ratio of anti-Stokes to Stokes signal extracted from SERS spectra vs in-coupling corrected laser intensity for the 1080 cm^-1 vibrational mode. Separate data files contain experimental data of individual NPoMs, this experimental data averaged in laser intensity bins (binned), as well as optomechanical simulations. Figure 3f: Ratio of anti-Stokes to Stokes signal extracted from SERS spectra vs in-coupling corrected laser intensity for the 1586 cm^-1 vibrational mode. Separate data files contain experimental data of individual NPoMs, this experimental data averaged in laser intensity bins (binned), as well as optomechanical simulations. Figure 4b: CW SERS spectra averaged over approx. 100 NPoMs on samples containing different mixing fractions of BPT and QTH molecules, 100% BPT, 76% BPT, 54% BPT, and 100% QTH. Figure 4c: Ratio of anti-Stokes to Stokes signal extracted from pulsed SERS spectra vs in-coupling corrected laser intensity for the 1080 cm^-1 vibrational mode, for samples with 100% BPT, 76% BPT, and 54% BPT. Experimental data of individual NPoMs is binned by laser intensity, with the error indicating the standard error of the average in the bin. Figure 4d: Optomechanical simulation of the anti-Stokes to Stokes ratio vs in-coupling corrected laser intensity for the 1080 cm^-1 vibrational mode. Separate files contain data of simulations with different numbers of molecules in the cavity, N = 217, 169, and 113 for 100% BPT, 75% BPT and 50% BPT, respectively. Figure 4e: Threshold intensity for vibrational pumping for different % BPT in the NPoM nanocavity. Separate files contain data from experiments and simulations. Figure 4f: Threshold intensity for vibrational pumping vs number of molecules in the cavity from optomechanical simulations. Figure 5a: Vibrational population of the 1080 cm^-1 vibrational mode vs laser intensity. Separate files contain the simulated effective population (calculated from simulated anti-Stokes to Stokes ratio), the simulated population of individual collective modes, as well as the experimental effective population (calculated from experimental anti-Stokes to Stokes ratio). Figure 5b: Vibrational population of the 1586 cm^-1 vibrational mode vs laser intensity. Separate files contain the simulated effective population (calculated from simulated anti-Stokes to Stokes ratio), the simulated population of individual collective modes, as well as the experimental effective population (calculated from experimental anti-Stokes to Stokes ratio). Figure 5c: Simulated spatial distribution of the first order collective vibrational mode of the 1080 cm^-1 vibration at laser intensity 1.2e7 uW um^-2. Figure 5d: Simulated spatial distribution of the first order collective vibrational mode of the 1586 cm^-1 vibration at laser intensity 1.2e7 uW um^-2.

Supplementary info: FigS7-S12: This data does not include any scaling.