Abstract: A method for achieving measurable sample heating in the vicinity of a probe microscope tip using Stimulated Raman Spectroscopy. Two laser sources, preferably in the UV visible or near IR illuminate the sample, preferably in overlapping diffraction limited spots. At least one of the sources is swept through a frequency range such that the difference frequency corresponds to IR spectral regions of interest. Selective Absorption by differing sample materials at the difference frequency causes measurable sample heating detectable by the probe tip related to IR spectral absorption bands. Thus very high spatial resolution IR spectroscopy may be achieved.

Abstract: An AFM based technique has been demonstrated for performing highly localized IR spectroscopy on a sample surface by using the AFM probe to detect wavelength dependent IR radiation interaction, typically absorption with the sample in the region of the tip. The tip may be configured to produce electric field enhancement when illuminated by a radiation source. This enhancement allows for significantly reduced illumination power levels resulting in improved spatial resolution by confining the sample-radiation interaction to the region of field enhancement which is highly localized to the tip.

Abstract: A method of obtaining submicron resolution IR absorption data from a sample surface. A probe microscope probe interacts with the sample surface while a tunable source of IR radiation illuminates the sample-tip interaction region. The source is modulated at a frequency substantially overlapping the resonant frequency of the probe and may be modulated at the contact resonance frequency of the probe when the probe is in contact with the sample surface. The modulation frequency is continually adjusted to account for shifts in the probe resonant frequency due to sample or other variations. A variety of techniques are used to observe such shifts and accomplish the adjustments in a rapid manner.

Abstract: Dynamic IR radiation power control for use in a nanoscale IR spectroscopy system based on an Atomic Force Microscope. During illumination from an IR source, an AFM probe tip interaction with a sample due to local IR sample absorption is monitored. The power of the illumination at the sample is dynamically decreased to minimize sample overheating in locations/wavelengths where absorption is high and increased in locations/wavelengths where absorption is low to maintain signal to noise.