Method, system and sensor for analysing a sample, and process for manufacturing an electrode

A method for analysing a sample comprising a layer having a first interface and a second interface, the method comprising: Irradiating the sample with a pulse of terahertz radiation, said pulse comprising a plurality of frequencies in the range from 0.01 THz to 10 THz; Detecting radiation reflected from the sample to produce a sample waveform; Obtaining a first reflection waveform from the sample waveform, the first reflection waveform corresponding to the reflection from the first interface; Obtaining a second reflection waveform from the sample waveform, the second reflection waveform corresponding to the reflection from the second interface; Comparing the first reflection waveform with the second reflection waveform to produce an estimate of a thickness and a complex refractive index of the layer; Producing a synthesised signal using the estimate of the thickness and complex refractive index; Varying at least one of the thickness and complex refractive index to reduce an error between the sample waveform a