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Multi-frequency CMUT imaging arrays for multi-scale imaging and imaging-therapy applications

Multi-frequency transducers may have a number of emerging applications including multi-scale imaging, superharmonc contrast imaging and imaging-therapy applications. For imaging-therapy applications low-frequencies are typically needed for therapeutic heating or contrast agent destruction, while higher-frequencies are required for high-resolution imaging. However, development of these multi-frequency transducers is challenging owing to disparate focal zones or difficult acoustic impedance matching. Recently we introduced CMUT-based multi-frequency transducers with small- and large- membranes interlaced on a scale smaller than the acoustic wavelengths. We have demonstrated the utility of small feasibility arrays for multi-band photoacoustic imaging but have yet to demonstrate co-aligned low-and-high frequency pulse-echo ultrasound with larger arrays.