Session Index

There has been plenty of interest and investigation in plasmonic metasurfaces to realize high-performance flat optical components and polarization converter devices [1, 2]. Most reported plasmonic metasurfaces are optimized under the realm of highly-radiative lossy electric and magnetic multipoles, which in fact limit their transmission efficiency [3]. As a result, plasmonic metasurfaces seem not very ideal for real applications in particular after introducing their dielectric counterparts. Nonetheless, it has been shown that dielectric metasurfaces cannot interact with the incident light as strongly as plasmonic structures. The requirement of a high aspect ratio in dielectric metasurfaces further devaluates their practical applications [4].
In this talk, I will present two strategies to realize high-performance metasurfaces for real-world applications. First, we draw our attention to modifying the model that is commonly used for designing a plasmonic metasurface for decades. We innovate a strategy to enhance the transmission efficiency of plasmonic metasurface to the highest attainable level [5, 6]. By integrating a solid nano-structure with its inverse complementary, we realized a plasmonic metasurface with a circular cross-polarization conversion efficiency higher than 50% in transmission at near-infrared wavelengths. Such high optical performance metasurface is achieved by simultaneously exciting the electric, magnetic, and toroidal multipolar modes, which satisfies the generalized Kerker condition and improves the transmission efficiency. We further demonstrate a couple of metasurface-based components such as a beam deflector and a flat focusing lens with record operating efficiency based on the proposed metasurface. Second, we switch the research topic from free space components to integrated devices. We propose that the polarization state of a lasing emission can be actively modulated at source with a metasurface-engaged microcavity, including highly circularly polarized, linearly polarized, or elliptically polarized lasing emission [7]. Taking advantage of strong optical feedback produced by the Fabry-Perot optofluidic microcavity, light-meta-atoms interactions will be enlarged, resulting in polarized lasing emission with high purity and controllability. These studies provide innovative insights into fundamental optics and laser physics, opening new possibilities by bridging metasurface into microlasers and practical applications.


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The focal length is invariable for most metalenses once they are fabricated. However, it is useful and cost-saving to realize reconfigurable metalenses for realistic applications, such as scanning microscopy and 3D imaging. Here, we designed an interleaved metasurface for dynamically-tunable metalens which enables continuous focal length tunability in the visible window.

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We experimentally demonstrate a monolithic platform to integrate metasurfaces and silicon photonic waveguides. This platform can generate free-space emission from waveguides and simultaneously control the emission phase and amplitude. We show generation of focused Gaussian beam, Hermite-Gaussian beam, and holographic projection from waveguides to the free space.

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Traditional diffractive or refractive elements need to accumulate phase during propagation, which are bulky and sizeable. Metasurfaces, composed of subwavelength structures, arbitrarily manipulate phase of electromagnetic waves and provide artificial planar optics and replace bulky diffractive elements for effectively manipulating light. In particular, integration of metasurface and semiconductor laser becomes the subject of growing interest in recent year. In this work, we demonstrate a compact meta-hologram PCSELs integration that diffracts ~750 beams to the free space. Such a random beam structured light could be implemented in a variety of optical applications such as facial recognition systems at near infrared.

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A new developed high-power light-source based partially corrugated gratings DFB is proposed here to overcome the challenging issues for the former datacenter network architecture, which suffers from cost production, bandwidth scalability, and power consumption. With HR-AR structure, grating ratio of 0.5, and κLg of 1.25, PCG-DFB can maintain a high output power of 128-mW, high slope efficiency of >0.33 mW/mA, reduced RIN of -155.157 dB/Hz, and good single-mode yield >91.89%. By integrating SOA length of 200-μm, improved output power of 4.64-dB can be achieved by PCG-DFB with length of 300-μm, grating ratio of 0.3, and grating strength of 5000 m-1.

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We report a microcavity laser whose circular polarization can be manipulated at the far field with the four grating waveguides surrounding a microdisk cavity. The lasing properties were characterized, and a high polarization degree of 50% was obtained.

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