Flat mirrors have been a consistent part of optical systems with a need to be included in devices such as microscopes and spectrometers Both the cases signify applications in which the limitations of flat mirrors are ever so important in the scope of modern optics, which has applications such as optical tweezers that require high focusing efficiency for trapping and rotation of particles Traditional invisible mirrors feature optical aberrations in off axis applications and further need multifunctional optical devices Metalenses are flat optics patterned with nanostructures, which have already given the potential for focusing and reflecting light without essential energy waste However, most conventional reflective metalenses are using a parabolic phase profile that reshapes the wavefront of the reflected beam The design based on lens models of the sphere leads to an often off the axis of propagation beam rays crossing the metalens nanoparticles, becoming specifically deviated upon them, with a loss of focal accuracy The paper presents a dielectric metalens based on the DMR structure and utilizes a dielectric Distributed Bragg Reflector ( to incorporate high reflection Accordingly, the so developed all dielectric reflector is aimed for the focusing of the incident electromagnetic waves having a wavelength in the visible range at a number of incidence angles, which, perhaps, may reduce major optical aberrations in off axis applications
An on-chip photoacoustic transducer is proposed by monolithically integrating piezoelectric micromachined ultrasonic transducers (PMUTs) on metasurface lenses for applications such as single-cell metabolic photoacoustic microscopy (SCM-PAM)1 . As shown in Figure 1a, every PMUT cell has a ring-shaped top electrode, and the membrane center is transparent without piezoelectric and electrode materials. The laser beam, therefore, can travel through a PMUT cell after being focused by a metasurface lens bonded on the backside of the PMUT (see Figure.3). The on-chip photoacoustic transducer fully leverages current PMUT and metasurface technologies and does not rely on transparent piezoelectric and electrode materials like typical transparent ultrasonic transducers2 . Moreover, the on-chip photoacoustic transducer has a monolithic integrated achromatic metasurface lens (see Figure 3), which can easily and efficiently focus the visible light (wavelength range: 400-700 nm) at the same focus point. Design and process this and preliminarily test the performance of PMUT and metasurface.
Bifocal and multifocal lenses allowing the incoming light to be focused at different focal spots can be applied in imaging, optical communication, and medical applications. In this study, we aim to solve the problems of multifocal lens design by using multilayer Pancharatnam-Berry (P-B) phase architecture. First, we will answer the fundamental question of what will happen when two layers of P-B phase elements are superimposed on each other. We show that a diffraction order with a phase shift equal to the rotation angle difference of the two layers can be observed. Based on this, we designed a multilayer metalens with arbitrary control of focal spot location and relative intensity.
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