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Nature Nanotechnology Jun 2023Metasurfaces have been rapidly advancing our command over the many degrees of freedom of light; however, so far, they have been mostly limited to manipulating light in...
Metasurfaces have been rapidly advancing our command over the many degrees of freedom of light; however, so far, they have been mostly limited to manipulating light in free space. Metasurfaces integrated on top of guided-wave photonic systems have been explored to control the scattering of light off-chip with enhanced functionalities-namely, the point-by-point manipulation of amplitude, phase or polarization. However, these efforts have so far been limited to controlling one or two optical degrees of freedom at best, as well as device configurations much more complex compared with conventional grating couplers. Here we introduce leaky-wave metasurfaces, which are based on symmetry-broken photonic crystal slabs that support quasi-bound states in the continuum. This platform has a compact form factor equivalent to the one of grating couplers, but it provides full command over the amplitude, phase and polarization (four optical degrees of freedom) across large apertures. We present devices for phase and amplitude control at a fixed polarization state, and devices controlling all the four optical degrees of freedom for operation at a wavelength of 1.55 μm. Merging the fields of guided and free-space optics through the hybrid nature of quasi-bound states in the continuum, our leaky-wave metasurfaces may find applications in imaging, communications, augmented reality, quantum optics, LIDAR and integrated photonic systems.
Topics: Optics and Photonics; Photons
PubMed: 37157023
DOI: 10.1038/s41565-023-01360-z -
Bioconjugate Chemistry Jan 2023Many photonic and electronic devices rely on nanotechnology and nanofabrication, but DNA-based approaches have yet to make a significant commercial impact in these... (Review)
Review
Many photonic and electronic devices rely on nanotechnology and nanofabrication, but DNA-based approaches have yet to make a significant commercial impact in these fields even though DNA molecules are now well-established as versatile building blocks for nanostructures. As we describe here, DNA molecules can be chemically modified with a wide variety of functional groups enabling nanocargoes to be attached at precisely determined locations. DNA nanostructures can also be used as templates for the growth of inorganic structures. Together, these factors enable the use of DNA nanotechnology for the construction of many novel devices and systems. In this topical review, we discuss four case studies of potential applications in photonics and electronics: carbon nanotube transistors, devices for quantum computing, artificial electromagnetic materials, and enzymatic fuel cells. We conclude by speculating about the barriers to the exploitation of these technologies in real-world settings.
Topics: Optics and Photonics; Computing Methodologies; Quantum Theory; Nanotechnology; Nanostructures; DNA; Electronics
PubMed: 36121896
DOI: 10.1021/acs.bioconjchem.2c00286 -
Biosensors & Bioelectronics Nov 2019Biosensor technology is an active field of research and development presenting rapid progress in recent decades, and the subfield of optical biosensors based on... (Review)
Review
Biosensor technology is an active field of research and development presenting rapid progress in recent decades, and the subfield of optical biosensors based on refractometric sensing schemes has developed dramatically during this time. This review focuses on advances in the refractometric sensing-based guided-wave optical biosensors particularly in the last two decades. It starts with a concise discussion on the underlying principles of label-free refractometric biosensor. Subsequently, advances in biosensor design, especially the transducer configuration and the integration of the sensing device are reviewed, highlighting the challenges and efforts dedicated to improving this technology. Various surface functionalization strategies designed to produce well-defined and reproducible surface properties are introduced for evaluation. Refractometric sensing scheme-based optical biosensors have found versatile applications varying from environmental monitoring and food safety to clinical diagnostics, together with advances in these applications and others are described. This paper concludes with a brief discussion on the outlook for integrating biosensors with emerging technologies.
Topics: Biosensing Techniques; Humans; Optics and Photonics; Pathology, Molecular; Refractometry
PubMed: 31539719
DOI: 10.1016/j.bios.2019.111693 -
The Journal of Physical Chemistry... Oct 2022Since the first optical detection of single molecules in 1989, single-molecule spectroscopy has developed rapidly and been widely applied in many areas. However, the... (Review)
Review
Since the first optical detection of single molecules in 1989, single-molecule spectroscopy has developed rapidly and been widely applied in many areas. However, the vast majority of matter is extremely inefficient at emitting photons in our physical world, which seriously limits the applications of optical methods based on photoluminescence. In addition to indirect detection by fluorescence labeling, many efforts have been made to directly image nonfluorescent matter at the single-particle or single-molecule level in different ways based on the absorption or scattering interaction between light and matter. Herein, we review five popular methods for imaging nonfluorescent particles/molecules, including dark-field microscopy (DFM), surface plasmon resonance microscopy (SPRM), surface enhanced Raman microscopy (SERM), interferometric scattering microscopy (iSCAT), and photothermal microscopy (PTM). After summarizing the principles and applications of these methods, we compare the advantages and disadvantages of each method and describe further potential development and applications.
Topics: Selective Estrogen Receptor Modulators; Nanotechnology; Surface Plasmon Resonance; Microscopy; Photons
PubMed: 36214484
DOI: 10.1021/acs.jpclett.2c02228 -
Nature Communications Mar 2021Interferometric scattering microscopy is increasingly employed in biomedical research owing to its extraordinary capability of detecting nano-objects individually...
Interferometric scattering microscopy is increasingly employed in biomedical research owing to its extraordinary capability of detecting nano-objects individually through their intrinsic elastic scattering. To significantly improve the signal-to-noise ratio without increasing illumination intensity, we developed photonic resonator interferometric scattering microscopy (PRISM) in which a dielectric photonic crystal (PC) resonator is utilized as the sample substrate. The scattered light is amplified by the PC through resonant near-field enhancement, which then interferes with the <1% transmitted light to create a large intensity contrast. Importantly, the scattered photons assume the wavevectors delineated by PC's photonic band structure, resulting in the ability to utilize a non-immersion objective without significant loss at illumination density as low as 25 W cm. An analytical model of the scattering process is discussed, followed by demonstration of virus and protein detection. The results showcase the promise of nanophotonic surfaces in the development of resonance-enhanced interferometric microscopies.
Topics: Crystallization; Equipment Design; Gold; Image Processing, Computer-Assisted; Metal Nanoparticles; Microscopy, Interference; Nanostructures; Optics and Photonics; Photons; Proteins; Virion; Viruses
PubMed: 33741998
DOI: 10.1038/s41467-021-21999-3 -
Reports on Progress in Physics.... Apr 2020Natural visual systems have inspired scientists and engineers to mimic their intriguing features for the development of advanced photonic devices that can provide better...
Natural visual systems have inspired scientists and engineers to mimic their intriguing features for the development of advanced photonic devices that can provide better solutions than conventional ones. Among various kinds of natural eyes, researchers have had intensive interest in mammal eyes and compound eyes due to their advantages in optical properties such as focal length tunability, high-resolution imaging, light intensity modulation, wide field of view, high light sensitivity, and efficient light management. A variety of different approaches in the broad field of science and technology have been tried and succeeded to duplicate the functions of natural eyes and develop bioinspired photonic devices for various applications. In this review, we present a comprehensive overview of bioinspired artificial eyes and photonic devices that mimic functions of natural eyes. After we briefly introduce visual systems in nature, we discuss optical components inspired by the mammal eyes, including tunable lenses actuated with different mechanisms, curved image sensors with low aberration, and light intensity modulators. Next, compound eye inspired photonic devices are presented, such as microlenses and micromirror arrays, imaging sensor arrays on curved surfaces, self-written waveguides with microlens arrays, and antireflective nanostructures (ARS). Subsequently, compound eyes with focal length tunability, photosensitivity enhancers, and polarization imaging sensors are described.
Topics: Animals; Biomimetics; Equipment Design; Eye, Artificial; Optics and Photonics
PubMed: 31923911
DOI: 10.1088/1361-6633/ab6a42 -
Nature Feb 2023
Topics: Biology; Microscopy
PubMed: 36750675
DOI: 10.1038/d41586-023-00336-2 -
Journal of Biomedical Optics May 2020Guest Editors introduce the Special Section on Photodynamic Therapy for the Journal of Biomedical Optics, Volume 25, Issue 6.
Guest Editors introduce the Special Section on Photodynamic Therapy for the Journal of Biomedical Optics, Volume 25, Issue 6.
Topics: Optics and Photonics; Photochemotherapy
PubMed: 32358929
DOI: 10.1117/1.JBO.25.6.063801 -
The Journal of Physical Chemistry... Jun 2022Entangled photon pairs are predicted to linearize and increase the efficiency of two-photon absorption, allowing continuous wave laser diodes to drive ultrafast...
Entangled photon pairs are predicted to linearize and increase the efficiency of two-photon absorption, allowing continuous wave laser diodes to drive ultrafast time-resolved spectroscopy and nonlinear processes. Despite a range of theoretical studies and experimental measurements, inconsistencies in the value of the entanglement-enhanced interaction cross section persist. A spectrometer that can temporally and spectrally characterize the entangled photon state before, during, and after any potential two-photon excitation event is constructed. For the molecule rhodamine 6G, which has a virtual state pathway, any entangled two-photon interaction is found to be equal to or weaker than classical, single-photon scattering events. This result can account for the discrepancies among the wide variety of entangled two-photon absorption cross sections reported from different measurement techniques. The reported instrumentation can unambiguously separate classical and entangled effects and therefore is important for the growing field of nonlinear and multiphoton entangled spectroscopy.
Topics: Models, Theoretical; Photons; Refractometry
PubMed: 35635002
DOI: 10.1021/acs.jpclett.2c00865 -
Journal of the Royal Society, Interface Apr 2021Quantifying and comparing light environments are crucial for interior lighting, architecture and visual ergonomics. Yet, current methods only catch a small subset of the...
Quantifying and comparing light environments are crucial for interior lighting, architecture and visual ergonomics. Yet, current methods only catch a small subset of the parameters that constitute a light environment, and rarely account for the light that reaches the eye. Here, we describe a new method, the environmental light field (ELF) method, which quantifies all essential features that characterize a light environment, including important aspects that have previously been overlooked. The ELF method uses a calibrated digital image sensor with wide-angle optics to record the radiances that would reach the eyes of people in the environment. As a function of elevation angle, it quantifies the absolute photon flux, its spectral composition in red-green-blue resolution as well as its variation (contrast-span). Together these values provide a complete description of the factors that characterize a light environment. The ELF method thus offers a powerful and convenient tool for the assessment and comparison of light environments. We also present a graphic standard for easy comparison of light environments, and show that different natural and artificial environments have characteristic distributions of light.
Topics: Eye; Humans; Optics and Photonics
PubMed: 33906390
DOI: 10.1098/rsif.2021.0184