This repository contains the original SNOM data and fits to them used in "Experimental signatures of the transition from acoustic plasmon to electronic sound in graphene" by D. Barcons Ruiz et al. - The Raw_data folder contains the original scans recorded with a neaSNOM (neaspec Gmbh) microscope for the two devices in .dump format. These data are easily accesible with Gwyddion. The first part of the filename indicates the date of acquisition and the scanning conditions. The suffix meaning of the individual scans within the raw data folders is: - First element: CT: topography MX: X-harmonic of the mechanical signal (piezo) BX: X-harmonic of the photocurrent signal - Second element: B/F: Backwards/Forward scans - Third element: abs: absolute value arg: phase (-pi to pi) Ex: 2022-02-02_10-48-16_2D-scan_4.25THz_GRp0.1V_GLsweep_m3Vtop1V_B1-B-abs.dump 2022-02-02: date 10-48-16: time 2D-scan: scan type 4.25THz: laser freq. GRp0.1V_GLsweep_m3Vtop1V: scan conditions B1-B-abs: 0th harmonic of the photocurrent signal, backwards trace, absolute value - The folder Figure2 contains the example traces extracted from the scans and shown in Fig.2 of the paper, and the fits to the optical signal, for both device 1 and 2. - The folder Figure3 contains the parameters obtained from the fitting of the plasmon fringes realizad as described in the Supplementary Information for both devices. The real part of the plasmon wavevector is used to calculate the plasmon velocity data appearing in Fig.3 A-B of the paper and constitutes the most important dataset. For every doubt on how to read or interpret these data please refer to the corresponding authors of the paper: Prof. F.H.L. Koppens (frank.koppens@icfo.eu), Dr. Iacopo Torre (iacopo.torre@icfo.eu).