Thus, when the laser is pulsed at a fixed frequency the Fourier transformed merely acts as a scaling factor that affects all A(β m , η n ) in the same way. Pulse width thus only affects the signal amplitude but not the spatial resolution. We can also see that the pulse width does affect overall signal amplitude. It reaches a maximum at t p = 1 2f and then decreases back down to 0 at t p = 1 f . Note that f here is not necessarily the laser repetition rate f rep but the frequency at which the signal is demodulated. Hence, when demodulating the AFM-IR signal at a multiple of the laser repetition rate (as is sometimes done to reach cantilever resonances beyond the maximum pulse repetition rate of the laser) care has to be taken, that the product of the demodulation frequency and pulse width f t p ≤ 0.5 (see the relationship between laser amplitude and duty cycle in Figure ). Increasing f t p > 0.5 does not increase the amplitude of the signal and only leads to unnecessary sample heating. (An illustration of the relationship between pulse width, amplitude and frequency can be found in Figure ).