Progress in Near-field Photothermal Infra-red Microspectroscopy

Near-field photothermal Fourier transform infra-red microspectroscopy, which utilizes atomic force microscopy (AFM)-type temperature sensors, is being developed with the aim of achieving a spatial resolution higher than the diffraction limit. Here we report on a new implementation of the technique. Sensitivity of the technique is assessed by recording infra-red spectra from small quantities of analytes and thin films. A photothermomechanical approach, which utilizes conventional AFM probes as temperature sensors, is also discussed based on preliminary results. Early indication suggests that the photothermal approach is more sensitive than the thermomechanical one.