Browsing by Subject "Acoustic levitation"

Omnidirectional microscopy (OM) is an emerging technology capable of enhancing the threedimensional (3D) microscopy widely applied in life sciences. In OM, precise position and orientation control are required for the sample. However, the current OM technology relies on destructive, mechanical methods to hold the samples, such as embedding samples in gel or attaching them to a needle to permit orientation control. A non-contacting alternative is the levitation of the sample. But, until now, the levitation methods have lacked orientation control. I enable omnidirectional access to the sample by introducing a method for acoustic levitation that provides precise orientation control. Such control around three axes of rotation permits imaging of the sample from any direction with a fixed camera and subsequent 3D shape reconstruction. The control of non-spherical particles is achieved using an asymmetric acoustic field created with a phase-controlled transducer array. The technology allows 3D imaging of delicate samples and their study in a time-lapse manner. I foresee that the described method is not only limited to microscopy and optical imaging, but is also compatible with automated sample handling, light-sheet microscopy, wall-less chemistry, and noncontacting tomography. I demonstrate the method by performing a surface reconstruction of three test samples and a biological sample. In addition, a simulation study and the levitation of test samples were used to characterize the levitation technique's performance. Both the shape reconstruction and orientation recovery were done by a computer vision based approach where the different images are stitched together. The results show the rotation stability and the wide angle range of the method.