The perfect optical vortex has successfully aroused substantial interest from researchers for its central dark hollow caused by spatial phase singularity in recent years. However, the traditional methods of combining axicon and helical to generate lead an additional focus deviation tightly focused systems. Here, we report a multi-foci integration (MFI) method produce accumulating finite number ...

The phased-array ultrasound transducer types are utilities for medical ultrasonography as well as optical imaging. However, their discontinuity characteristic limits the applications due to the artifacts contaminated into the reconstructed images. Because of the effects of the ultrasound pressure field pattern to the echo ultrasonic waves as well as the optical modulated signal, the side lobes ...