Systems and methods for performing truncated-correlation photothermal coherence tomography

Abstract

Photothermal imaging systems and methods are disclosed that employ truncated-correlation photothermal coherence tomography (TC-PCT). According to the example methods disclosed herein, photothermal radiation is detected with an infrared camera while exciting a sample with the chirped delivery of incident laser pulses (where the pulses have a fixed width), and time-dependent photothermal signal data is obtained from the infrared camera and processed using a time-evolving filtering method employing cross-correlation truncation. The cross-correlation truncation method results in pulse-compression-linewidth-limited depth-resolved images with axial and lateral resolution well beyond the well-known thermal-diffusion-length-limited, depth-integrated nature of conventional thermographic and thermophotonic modalities. As a consequence, an axially resolved layer-by-layer photothermal image sequence can be obtained, capable of reconstructing three-dimensional visualizations (tomograms) of photothermal features in wide classes of materials. Additional embodiments are disclosed in which the aforementioned systems and methods are adapted to photo-acoustic and acousto-thermal imaging.