A novel technique is presented for micro-endoscopy in which ultrasonic waves will alter the optical properties of tissue for sculpting virtual optical waveguides with graded refractive index profiles to guide and focus photons through the medium. Using this technique, images of target objects can be relayed through a turbid medium without implanting a physical endoscope. We demonstrate imaging of fluorescent objects with feature sizes as small as 22 µm through a scattering tissue phantom. The presented method can also enable in situ volumetric scanning of the medium by changing the pattern and intensity of ultrasonic waves. We demonstrate that arbitrary patterns of light can be sculpted in the target medium in the form of dipole, quadrupole and higher-order beam patterns using a multi-segment cylindrical ultrasonic array.
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