Young Min Song

• Professor (Associate) at Gwangju Institute of Science and Technology

In arthropods, evolution has created a remarkably sophisticated class of imaging systems, with a wide-angle field of view, low aberrations, high acuity to motion and an infinite depth of field. A challenge in building digital cameras with the hemispherical, compound apposition layouts of arthropod eyes is that essential design requirements cannot b...

The diverse vision systems found in nature can provide interesting design inspiration for imaging devices, ranging from optical subcomponents to digital cameras and visual prostheses, with more desirable optical characteristics compared to conventional imagers. The advantages of natural vision systems include high visual acuity, wide field of view,...

Conventional wide-field-of-view cameras consist of multi-lens optics and flat image sensor arrays, which makes them bulky and heavy. As a result, they are poorly suited to advanced mobile applications such as drones and autonomous vehicles. In nature, the eyes of aquatic animals consist of a single spherical lens and a highly sensitive hemispherica...

Covert polarization displays provide a barrier to the inadvertent viewing of stored optical information. For security and anti‐counterfeiting purposes, access to concealed information without compromising packaging aesthetics is required in certain situations. However, optical conversion with polarized light typically requires sophisticated nanostr...

Acclimatable colors in response to environmental stimuli, which are naturally endowed with some living things, can provide an opportunity for humans to recognize hazardous substances without taking empirical risks. Despite efforts to create artificial responsive colors, realistic applications in everyday life require an immediate/distinct colorimet...

Solid‐state refrigeration based on the electrocaloric (EC) effect has recently been applied to thermal management for humans and electronics due to its low power consumption, zero carbon emissions, and compact size. However, the temperature span of the EC device is limited by the adiabatic temperature change (ΔTad) of the caloric materials. Moreove...

Passive radiative cooling is a promising energy‐saving strategy for space cooling. Dual‐sided thermal emitters offer efficient heat removal from enclosed spaces; however, existing studies predominantly focus on rooftop applications, with limited attention to vertical surfaces, such as walls and windows. Here, a dual‐sided radiative cooling glass (D...

The increasing demand for visual data processing reveals the limitations of traditional electronic systems in speed, energy efficiency, and adaptability. While optical computing offers a promising alternative, current systems often lack the flexibility required for multispectral and adaptive visual tasks. Here, we present an efficient way for highl...

This paper describes laser exposure to tune the infrared (IR) emissivity of a film of eutectic gallium indium (EGaIn) particles. EGaIn – a liquid metal at room temperature – forms a native oxide that keeps particles of the metal from spontaneously percolating. Photothermal energy from a CO2 laser percolates the particles into a conductive network....

By monitoring brain neural signals, neural recorders allow for the study of neurological mechanisms underlying specific behavioural and cognitive states. However, the large brain volumes of non-human primates and their extensive range of uncontrolled movements and inherent wildness make it difficult to carry out covert and long-term recording and a...

Artificial antireflective nanostructured surfaces, inspired by moth eyes, effectively reduce optical losses at interfaces, offering significant advantages in enhancing optical performance in various optoelectronic applications, including solar cells, light-emitting diodes, and cameras. However, their limited flexibility and low surface hardness con...

Fast-responsive colorimetric sensors with a wide color gamut have garnered significant attention for real-time atmospheric monitoring observable to the naked eye. Although swelling medium-based Fabry–Perot cavities, which enable linear resonance shifts with high Q-factors, have been widely suggested, they face limitations such as a restricted color...

In robotics, particularly for autonomous navigation and human–robot collaboration, the significance of unconventional imaging techniques and efficient data processing capabilities is paramount. The unstructured environments encountered by robots, coupled with complex missions assigned to them, present numerous challenges necessitating diverse visua...

Biologically inspired artificial vision research has led to innovative robotic vision systems with low optical aberration, wide field of view, and compact form factor. However, challenges persist in object detection and recognition against complex backgrounds and varied lighting. Inspired by the feline eye, which features a vertically elongated pup...

The bioinspired camera, comprising a single lens and a curved image sensor—a photodiode array on a curved surface—, was born of flexible electronics. Its economical build lends itself well to space-constrained machine vision applications. The curved sensor, much akin to the retina, helps image focusing, but the curvature also creates a problem of i...

When implementing optoelectronic devices through the stacking of heterogeneous materials, considering the bandgap offset is crucial for achieving efficient carrier dynamics. In this study, the bandgap offset characteristics are investigated when n‐type gallium nitride nanowires (n‐GaN NWs) are used as electron transport layers in methylammonium lea...

Avian eyes have deep central foveae as a result of extensive evolution. Deep foveae efficiently refract incident light, creating a magnified image of the target object and making it easier to track object motion. These features are essential for detecting and tracking remote objects in dynamic environments. Furthermore, avian eyes respond to a wide...

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The field of flexible optoelectronics is broad and multi-disciplinary, and draws upon knowledge in fields ranging from, amongst others, optics and photonics; organic or inorganic materials; device physics/engineering; nanoscience and nanoengineering; mechanics; neuroscience; signal processing; computing; and bioscience.

Bioresorbable neural implants based on emerging classes of biodegradable materials offer a promising solution to the challenges of secondary surgeries for removal of implanted devices required for existing neural implants. In this study, we introduce a fully bioresorbable flexible hybrid opto-electronic system for simultaneous electrophysiological...

Artificial vision systems pervade our daily lives as a foremost sensing apparatus in various digital technologies, from smartphones to autonomous cars and robotics. The broad range of applications for conventional vision systems requires facile adaptation under extreme and dynamic visual environments. However, these current needs have complicated i...

Adaptive multicolor filters have emerged as key components for ensuring color accuracy and resolution in outdoor visual devices. However, the current state of this technology is still in its infancy and largely reliant on liquid crystal devices that require high voltage and bulky structural designs. Here, we present a multicolor nanofilter consisti...

Advances in nanophotonics have created numerous pathways for light–matter interactions in nanometer scale, enriched by physical and chemical mechanisms. Over the avenue, electrically tunable photonic response is highly desired for optical encryption, optical switch, and structural color display. However, the perceived obstacle, which lies in the en...

Passive radiative cooling has emerged as a sustainable energy-saving solution, characterized by its energy-free operation and absence of carbon emissions. Conventional radiative coolers are designed with a skyward orientation, allowing for efficient heat dissipation to the cold heat sink. However, this design feature presents challenges when instal...

Reconfigurable optical devices hold great promise for advancing high‐density optical interconnects, photonic switching, and memory applications. While many optical modulators based on active materials have been demonstrated, it is challenging to achieve a high modulation depth with a low operation voltage in the near‐infrared (NIR) range, which is...

Precise monitoring of neurotransmitters, such as dopamine (DA), is critical for understanding brain function and treating neurological disorders since dysregulation of DA implicates in a range of disorders, including Parkinson's disease (PD), schizophrenia, and addiction. This study proposes a multi‐deformable double‐sided (MDD) DA‐sensing probe wi...

Numerous wireless optogenetic systems have been reported for practical tether-free optogenetics in freely moving animals. However, most devices rely on battery-powered or coil-powered systems requiring periodic battery replacement or bulky, high-cost charging equipment with delicate antenna design. This leads to spatiotemporal constraints, such as...

Fano resonance, known for its unique asymmetric line shape, has gained significant attention in photonics, particularly in sensing applications. However, it remains difficult to achieve controllable Fano parameters with a simple geometric structure. Here, a novel approach of using a thin-film optical Fano resonator with a porous layer to generate e...

Phase Change Materials (PCMs) have demonstrated tremendous potential as a platform for achieving diverse functionalities in active and reconfigurable micro-nanophotonic devices across the electromagnetic spectrum, ranging from terahertz to visible frequencies. This comprehensive roadmap reviews the material and device aspects of PCMs, and their div...

A significant threat of health problems with serious stress endangers outdoor workers who are in an exceedingly hot workplace. Although recent studies promise to quantify stress levels on the human skin, they still rely on rigid, bulky sensor modules, causing data loss from motion artifacts and limited field‐deployability for continuous health moni...

Thermal management for wearable devices is evolving to make ubiquitous applications possible based on advanced devices featuring miniaturization, integration, and ultrathin designs. Thermal management and control integrated with wearable devices are highly desirable for various applications for human body monitoring, including external heat exposur...

Passive radiative cooling has been spotlighted as a promising energy-saving cooling technology owing to its energy-free and zero-carbon emission for addressing global energy and climate crises. Although radiative cooling can significantly save cooling energy in hot weather, it inevitably accompanies undesirable cooling in cold weather resulting fro...

With the rise of mobile robotics, including self-driving automobiles and drones, developing artificial vision for high-contrast and high-acuity imaging in vertically uneven illumination conditions has become an important goal. In such situations, balancing uneven illumination, improving image contrast for facile object detection, and achieving high...

Recent advances in passive radiative cooling systems describe a variety of strategies to enhance cooling efficiency, while the integration of such technology with a bioinspired design using biodegradable materials can offer a research opportunity to generate energy in a sustainable manner, favorable for the temperature/climate system of the planet....

Over the past few decades, advances in various nanophotonic structures to enhance light–matter interactions have opened numerous opportunities for biosensing applications. Beyond the successful development of label-free nanophotonic biosensors that utilize plasmon resonances in metals and Mie resonances in dielectrics, simpler structures are requir...

In the natural evolutionary process, biological creatures have developed diverse visual structures apt for their habitational environments. These natural vision structures have inspired the development of artificial vision systems. These...

We present a bi-directional Fano resonator, which is capable of spectral shape control by adjusting the continuum state. By addressing the reflection phase, we demonstrate sensitive-chromatic response for color control with viral-particle sensing ability (SARS-COV-2).

We present an inverse design approach for spectral line shapes using thin-film-based Fano resonators. Stochastic gradient descent (SGD)-based learning provides CMOS-compatible process parameters for spectral line shapes with four different Fano q parameters.

We present our recent advances in the building of artificial vision systems inspired by the eyes of aquatic animals, including fishes, cephalopods, and crabs. The complete set of bioinspired eyes shows exceptional imaging capabilities.

We present a compact reconstructive micro-spectrometer based on a linear variable filter consisting of multi-layer stacks with random thicknesses in the spatial domain. A simple gradient deposition/rotation method enables wafer-scale random filters with an encryption function.

Treatment trends for Parkinson’s disease are revolutionizing from conventional pharmaceutical treatment depending on the patient’s symptoms to closed-loop electroceutical treatment in order to minimize the crucial pharmacokinetic drawbacks. Over the decades, closed-loop neuromodulations have been achieved by electroceutical devices based on continu...

The increasing advances in thermal radiation regulators have attracted growing interest, particularly in infrared sources, thermal management, and camouflage. Despite many advances in dynamic thermal emitters with great controllability, sustained external energy is required to maintain the desired emission. In this study, we present a polarization-...

Humidity‐responsive structural coloration is actively investigated to realize real‐time humidity sensors for applications in smart farming, food storage, and healthcare management. Here, humidity‐tunable nano pixels are investigated with a 700 nm resolution that demonstrates full standard RGB (sRGB) gamut coverage with a millisecond‐response time....

Triple-negative breast cancer (TNBC) is a form of breast cancer that is more aggressive and harder to treat than others, with a higher probability of relapse. Its nefarious capabilities for migrating and invading other parts of the body together with the current lack of clinically established effective therapies account for a low survival rate. In...

A facile approach for improving color purity is explored by the introduction of an angle-robust selective absorber (ARSA) into bottlebrush block copolymer (BBCP)-based one-dimensional (1D) photonic crystals (PCs). The BBCPs of poly[(3-(12-(cis-5-norbornene-exo-2,3-dicarboximido)dodecanoylamino)propyl POSS)-block-(norbornene-graft-styrene)], Px (x =...

High-performance photodetecting materials with intrinsic stretchability and colour sensitivity are key requirements for the development of shape-tunable phototransistor arrays. Another challenge is the proper compensation of optical aberrations and noises generated by mechanical deformation and fatigue accumulation in a shape-tunable phototransisto...

Transformative Electronics Gallium‐based transformative electronics, which can convert between handheld and wearable forms, are vulnerable to a hot outdoor environment, which leads to unwanted softening of the electronics due to liquefaction of gallium. For the reliable rigid‐mode operation in hot outdoors, the transformative electronics integratin...

The next frontier of photonics is evolving into reconfigurable platforms with tunable functions to realize the ubiquitous application. The dynamic control of optical properties of photonics is highly desirable for a plethora of applications, including optical communication, dynamic display, self-adaptive photonics, and multi-spectral camouflage. Re...

Biological visual systems have inspired the development of various artificial visual systems including those based on human eyes (terrestrial environment), insect eyes (terrestrial environment) and fish eyes (aquatic environment). However, attempts to develop systems for both terrestrial and aquatic environments remain limited, and bioinspired elec...

Radiative cooling, which is based on radiative heat exchange between the universe and Earth, can provide a passive and renewable route to reducing energy consumption. Radiative cooling was historically limited to nighttime applications owing to a lack of solar reflectivity. However, recent advances in photonics have facilitated the realization of m...

Reconfigurability of a device that allows tuning of its shape and stiffness is utilized for personal electronics to provide an optimal mechanical interface for an intended purpose. Recent approaches in developing such transformative electronic systems (TES) involved the use of gallium liquid metal, which can change its liquid–solid phase by tempera...

Bioparticle Imaging and Analysis In article number 2110003, Dae‐Hyeong Kim, Young Min Song, and co‐workers propose an intuitive and robust approach for the label‐free bright‐field imaging and facile quantification of bioparticles using a Gires–Tournois immunoassay platform (GTIP). The particle distribution and density on the surface of the resonato...

The long-fascinated idea of creating 3D images that depict depth information along with color and brightness has been realized with the advent of a light-field camera (LFC). Recently advanced LFCs mainly utilize micro-lens arrays (MLAs) as a key component to acquire rich 3D information, including depth, encoded color, reflectivity, refraction, occl...

Bright‐field imaging of nanoscale bioparticles is a challenging task for optical microscopy because the light‐matter interactions of bioparticles are weak on conventional surfaces due to their low refractive index and small size. Alternatively, advanced imaging techniques, including near‐field microscopy and phase microscopy, have enabled visualiza...

Perovskite microcells have a great potential to be applied to diverse types of optoelectronic devices including light-emitting diodes, photodetectors, and solar cells. Although several perovskite fabrication methods have been researched, perovskite microcells without a significant efficiency drop during the patterning and fabrication process could...

Conventional radiative cooling devices are white or silver in color to achieve high reflectance in the solar spectral range. However, a versatile color that can be applied to the radiative cooler is required for practical application. To determine the boundary between coloration and cooling performance, the reflectance in the visible range should b...

The development of real-time and sensitive humidity sensors is in great demand from smart home automation and modern public health. We hereby proposed an ultrafast and full-color colorimetric humidity sensor that consists of chitosan hydrogel sandwiched by a disordered metal nanoparticle layer and reflecting substrate. This hydrogel-based resonator...

Solar Cells In article number 2103258 Young Min Song, Gil Ju Lee and co‐workers evaluate the effectiveness of radiative cooler (RC)‐integrated solar cells (SCs) quantitatively. The authors theoretically and experimentally reveal that all SCs benefit from RCs, however, multi‐junction SCs are the most effective SCs. The cover image conceptually liken...

A compact single‐material Tamm plasmon (TP) structure in the near‐infrared was theoretically designed and experimentally verified by Young Min Song and co‐workers, as shown in article number 2102388. The TP is composed of a single material, where the refractive indices are tailored through porosity tuning to achieve impedance matching. The fabricat...

Efficient Image Recognition In article number 2100144, Young Min Song, Dae‐Hyeong Kim, and colleagues present remarkable technological advances in terms of the efficient image recognition. These achievements are due in large to the recent development in the bio‐inspired artificial vision and the neuromorphic image processing devices.

For modern security, devices, individuals, and communications require unprecedentedly unique identifiers and cryptographic keys. One emerging method for guaranteeing digital security is to take advantage of a physical unclonable function. Surprisingly, native silk, which has been commonly utilized in everyday life as textiles, can be applied as a u...

As a powerful planar plasmonics, Tamm plasmon (TP) structures open up new possibilities for high‐efficiency photonic applications demanding high quality (Q)‐factor with scalability and spectral tunability. Despite the theoretical advantages of TP structures, TP configurations alternately stacked within limited materials and integer ranges result in...

In this study, we investigated the dependency of the radiative cooling power for various types of solar cell(SC)s. As a result, high efficient multi-junction solar cell(MJSC) is presented by introducing bi-functional radiative cooler.