1. Method of measuring a localized IR spectra of a sample comprising; interacting an AFM probe with a region of a sample; illuminating the sample with pulsed variable wavelength IR radiation at a pulse frequency at or near a resonant frequency of the AFM probe with at least one of an Optical Parametric Oscillator or a Quantum Cascade laser as an IR source; collecting deflection data from the probe due to exciting a resonant oscillation of the probe in response to thermal expansion of the sample due to absorption of radiation from the IR; and, repeating the collecting step while varying IR radiation wavelength to create an IR absorption spectrum from the deflection data.