This effect, too, is due to the increasing duty cycle and thus increasing energy deposited in the absorber. This effect is not true for arbitrary long pulse widths, as will be discussed below. As the PSF model can describe the signal of a three dimensional absorber, in addition to time/frequency domain behaviour 9 it can also describe the lateral extension of the deflection caused by an absorber, which allows to determine the spatial resolution of the AFM-IR measurement. In general, modes with higher β m will lead to a narrower profile due to the only r dependent term J 0 (β m r) in (8). These narrower modes will have a faster decay in time as λ mn increases with m affecting the time dependent term T mn (t) defined in (7).