This dataset contains experimental results supporting the research article titled 'Third Harmonic Mie Scattering From Semiconductor Nanohelices'. The 'Linear_CD' folder contains results of chiral optical (chiroptical) characterisation in the linear optical regime of both of the enantiomorphs (L- and D-) of CdTe helices dispersed in a solvent (0.2 % of sodium dodecyl sulfate in water). Spectra of the solvent were measured first. These reference measurements were then automatically subtracted from the circular dichroism spectra of the samples. Each sample was measured in two wavelength ranges. A different detector was used for each of the ranges - measurements in the near infrared range have 'IR' in their file name. Each measurement was done three times - the individual measurements are in separate columns in the csv files. The 'Differential_extinction_cross-section' folder contains the output files of simulations performed in Lumerical. The simulations are discussed in greater detail in the associated publication and its supplementary information. The 'Emission_patterns' folder contains a report exported from Comsol Multiphysics detailing the setup and results of simulations of the scattering patterns produced by an L-CdTe helix. The folders called 'Polarisation-...' contain measurements of third harmonic (TH) scattering at 90 degrees with respect to the incident laser beam and in the forward direction (as indicated in the folder name) for various incident polarisations and multiple angles of the analysing quarter-wave. '45' or '135' after 'QWP' in the file names indicates the orientation of the quarter-wave plate in the illumination arm of our experimental setup. '45' and '135' correspond to left and right circular polarisation, respectively. The numbers after 'AQWP' in the file names represent the angle of the analysing quarter-wave plate. An angle of 0 degrees means the fast axis of the wave plate was horizontal. The .shg files are text files containing two columns. The second column contains the measured TH intensity in counts/second. The folder called 'Emission' contains measurements of nonlinear emission under illumination with 1095-nm light. Each file name includes a number after 'QWP', which determines the polarisation of the incident light ('45' - left circular polarisation, '90' - linear polarisation, '90' - right circular polarisation). The number at the end of the file name indicates the central transmission wavelength of the filter in front of the detector. Each of the text files contains four columns. The second column contains measurements of light emitted at 90 degrees with respect to the incident beam (intensity in counts/second). The first and the last numbers in the third column are reference measurements - measurements of TH generation from Z-cut quartz. The other numbers in the column are measurements of forward emission by the sample (intensity in counts/second). The folders whose name starts 'Power_dependence-...' contain measurements of TH intensity as a function of incident power for incident left circularly polarised light ('QWP_45' in the file name) and right circularly polarised light ('QWP_135' in the file name). The power was controlled by a half-wave plate placed in front of a polariser. The angle of the half-wave plate is specified in the file name after 'HWP'. The text files contain four columns. The second and the third columns have the same meaning as for the files in the 'Emission' folder. The power dependence measurements were performed for cells with 1 mm and 10 mm pathlength, as specified in the folder name. In the case of the 1-mm cells, the second column of the files contains no useful data. The files whose name starts 'Power_calibration-...' contain measurements of TH generation by Z-cut quartz as a function of incident laser power for various incident wavelengths (as specified in the file name). The measured power dependence can be fitted with a function of the form y=Ax^3, where A is a constant. The obtained A can then be used to calculate the incident power in the measurements in the 'Power_dependence-...' folders (based on the reference measurements in the files).