Micro- and nanocantilevers, which have traditionally played a vital role in the development of force microscopy, and more recently a special role in biological, chemical and physical sensing and detection, have received comparatively little attention in optical spectroscopy. We present an investigation of the optical response of microcantilevers towards their utilization in integrated spectrometers in a broad part of the spectrum. By discussing the overall actuation mechanism we describe how surface modes may effectively contribute to the final signal. Using Fourier transform infrared (FTIR) spectroscopy, a series of multilayered microcantilevers are characterized for their spectral response in the range from 7800 to 400 cm¡1. Transmission FTIR and FTIR photothermal spectroscopy are carried out using polystyrene with well-established infrared spectra.