Photoacoustic imaging using a conical axicon detector

Photoacoustic imaging with a scanning, fixed focus receiver gives images with high resolution, without the need for image reconstruction. For achieving high depth of field, a conically shaped piezoelectric ultrasound detector, the so called axicon-detector, is investigated. It is characterized by a sustained line of focus with a length that depends only on the geometry of the detector but not on the wavelength. Simulated and experimentally taken images of various objects reveal X-shaped artifacts due to the conical surface of the detector. To improve the image quality a frequency domain deconvolution can be applied, as the point spread function (PSF) of the detector is spatially invariant over the depth of field. The reduction of the artifacts works well for simulated images but is not functional for experimental data yet. Nevertheless, the detector gives images with precise shape and position of the investigated samples.