Fourier transform spectrometer and method of Fourier transform spectroscopy

A Fourier transform spectrometer comprising an interferometer comprising a fixed mirror, a movable mirror, a circuit, an electrode and a detector, wherein:

• the mirrors are positioned parallel to each other and form an optical cavity;
• the movable mirror is operable to move relative to the fixed mirror to change the length of the optical cavity;
• a first mirror of the mirrors is positioned such that light received enters the optical cavity through a back of the first mirror;
• the detector is positioned and operable to detect light which has exited the optical cavity through a back of the second mirror of the mirrors and output an interferogram;
• the mirrors are distanced from each other such that the movable mirror is at or can move to a position where at least two optical paths to the detector for received light reflected within the interferometer are of equal length;
• the movable mirror and electrode positioned at a distance from each other and the circuit connected to the movable mirror and the electrode and operable to apply an electric field between them to move the movable mirror with respect to the fixed mirror;
• and the electrode is positioned such that the movable mirror lies between the fixed mirror and the electrode.