The data in the attached folder are those required to support the findings in the related manuscript.

1) Figure 2a.
- fig2a_data.csv. Spectral noise density. First column: input power in microwatt; second column: spectral noise density in microvolt/sqrt(Hz); third column: error on the values in the second column; fourth column: error on the values of the first column.
2) Figure 2b
- fig2b_noise_reduction_data.csv. First Column: input power in microwatt; second column: noise reduction factor in dB; third column: standard deviation of the noise reduction factor in dB.
- fig2b_noise_reduction_fit.csv. Data to plot the fit.  First Column: input power in microwatt; second column: noise reduction factor in dB; 
- fig2b_noise_ratio.csv: ratio between total noise and electric noise vs input power. First column: input power in microwatt; second column: ratio between total noise and electric noise; third column: error on the ratio between total noise and electric noise; fourth column: error on the input power in microwatt.
3) Figure 3a. ‘fig3a.csv’. Classical and quantum THz trace. First column: time axis for the classical trace in picoseconds; second column: THz signal with the classical probe in microvolts; third column: time axis for the quantum trace in picoseconds; fourth column: THz amplitude signal for the quantum probe in microvolts.
4) Figure 3b. ‘fig3b.csv’. Noise on the THz signal. First column: time axis for the classical measurement in picoseconds; second column: noise on the THz signal measured with the classical probe in microvolts; third column: time-average of the noise on the THz signal measured with the classical probe in microvolts; fourth column: time axis for the quantum measurement in picoseconds; fifth column: error on the THz signal measured with the quantum probe in microvolts; sixth column: time-average of the noise on the THz signal measured with the quantum probe in microvolts.
5) Figure 3c and 3d. ‘fig3cd.csv’. Normalized electric field values at the THz peak over 1m acquisition. First column: acquisition time in seconds; second column: peak THz field (normalized) value acquired with the classical probe; third column: peak THz field (normalized) value acquired with the quantum probe;
6) Figure 4: spectral comparison.
- ‘fig4_PSD.csv’: power spectral density. First column: frequency axis for the PSD from the classical measurement in THz; second column: PSD (normalized) obtained from the classical measurement; third column: error on the normalized PSD obtained from the classical measurement; fourth column: frequency axis for the PSD from the quantum measurement in THz; fifth column: PSD (normalized) obtained from the quantum measurement; sixth column: error on the normalized PSD obtained from the quantum measurement;
- ‘fig4_NRF.csv’: Sensitivity improvement factor in the spectral domain. First column: frequency axis for the in THz; second column: Sensitivity improvement factor for the spectral amplitude; third column: Sensitivity improvement factor for the spectral phase