Exciton reservoir-induced destabilization and reformation of polariton condensate.

We investigate the dynamics of a driven-dissipative polariton condensate in a GaAs microcavity under simultaneous excitations by a continuous laser and a pulsed laser. The femtosecond pulse destabilizes and quenches the condensate, which is then followed by a nonlinear luminescence surplus. Time-resolved photoluminescence shows a ring-like pattern in momentum space that shrinks as the condensate relaxes back to its steady state.

Over a thousand-fold enhancement of the spontaneous emission rate for stable core-shell perovskite quantum dots through coupling with novel plasmonic nanogaps.

High Purcell enhancement structures and stable emitters are essential prerequisites for the successful development of novel fast-operating active devices. Furthermore, a uniform enhancement of the spontaneous emission rate is critical for practical applications. Despite considerable efforts being made to meet these requirements, achieving them still remains a challenging task.

Tailored fabrication of a self-rolled-up AlGaN/GaN tubular structure with photoelectrochemical etching.

Group III-nitride semiconductors with tubular structures offer significant potential across various applications, including optics, electronics, and chemical sensors. However, achieving tailored fabrication of these structures remains a challenge. In this study, we present a novel, to the best of our knowledge, method to fabricate micro-sized tubular structures by rolling the layered membrane of group III-nitride alloys utilizing the photoelectrochemical (PEC) etching.

Ultrafast and Bright Quantum Emitters from the Cavity-Coupled Single Perovskite Nanocrystals.

Perovskite nanocrystals (NCs) have attracted increasing interest in the realization of single-photon emitters owing to their ease of chemical synthesis, wide spectral tunability, fast recombination rate constant, scalability, and high quantum yield. However, the integration of a single perovskite NC into a photonic structure has yet to be accomplished. In this work, the integration of a highly stable individual zwitterionic ligand-based CsPbBr perovskite NC with a circular Bragg grating (CBG) is successfully demonstrated.

Deep-learning-based gas identification by time-variant illumination of a single micro-LED-embedded gas sensor.

Electronic nose (e-nose) technology for selectively identifying a target gas through chemoresistive sensors has gained much attention for various applications, such as smart factory and personal health monitoring. To overcome the cross-reactivity problem of chemoresistive sensors to various gas species, herein, we propose a novel sensing strategy based on a single micro-LED (μLED)-embedded photoactivated (μLP) gas sensor, utilizing the time-variant illumination for identifying the species and concentrations of various target gases. A fast-changing pseudorandom voltage input is applied to the μLED to generate forced transient sensor responses.

Scannable Dual-Focus Metalens with Hybrid Phase.

Metalenses with two foci in the longitudinal or transverse direction, called bifocal or dual-focus metalenses, are promising building blocks in tomography techniques, data storage, and optical tweezers. For practical applications, relative movement between the beam and specimen is required, and beam scanning is highly desirable for high-speed operation without vibration. However, dual-focus metalenses employ a hyperbolic phase that experiences off-axis aberrations, which is not suitable for beam scanning.

Nanowatt-Level Photoactivated Gas Sensor Based on Fully-Integrated Visible MicroLED and Plasmonic Nanomaterials.

Photoactivated gas sensors that are fully integrated with micro light-emitting diodes (µLED) have shown great potential to substitute conventional micro/nano-electromechanical (M/NEMS) gas sensors owing to their low power consumption, high mechanical stability, and mass-producibility. Previous photoactivated gas sensors mostly have utilized ultra-violet (UV) light (250-400 nm) for activating high-bandgap metal oxides, although energy conversion efficiencies of gallium nitride (GaN) LEDs are maximized in the blue range (430-470 nm). This study presents a more advanced monolithic photoactivated gas sensor based on a nanowatt-level, ultra-low-power blue (λ  = 435 nm) µLED platform (µLP).

Single Quantum Dot Selection and Tailor-Made Photonic Device Integration using a Nanoscale-Focus Pinspot.

Among the diverse platforms of quantum light sources, epitaxially grown semiconductor quantum dots (QDs) are one of the most attractive workhorses for realizing quantum photonic technologies owing to their outstanding brightness and scalability. However, the spatial and spectral randomness of most QDs severely hinders the construction of large-scale photonic platforms. In this work, a methodology is presented to deterministically integrate single QDs with tailor-made photonic structures.

Electrically Driven Sub-Micrometer Light-Emitting Diode Arrays Using Maskless and Etching-Free Pixelation.

For decades, group-III-nitride-based light-emitting diodes (LEDs) have been regarded as a light emitting source for future displays by virtue of their novel properties such as high efficiency, brightness, and stability. Nevertheless, realization of high pixel density displays is still challenging due to limitations of pixelation methods. Here, a maskless and etching-free micro-LED (µLED) pixelation method is developed via tailored He focused ion beam (FIB) irradiation technique, and electrically driven sub-micrometer-scale µLED pixel arrays are demonstrated.

Dielectric-Engineered High-Speed, Low-Power, Highly Reliable Charge Trap Flash-Based Synaptic Device for Neuromorphic Computing beyond Inference.

The coming of the big-data era brought a need for power-efficient computing that cannot be realized in the Von Neumann architecture. Neuromorphic computing which is motivated by the human brain can greatly reduce power consumption through matrix multiplication, and a device that mimics a human synapse plays an important role. However, many synaptic devices suffer from limited linearity and symmetry without using incremental step pulse programming (ISPP).

Ultra-Low-Power E-Nose System Based on Multi-Micro-LED-Integrated, Nanostructured Gas Sensors and Deep Learning.

As interests in air quality monitoring related to environmental pollution and industrial safety increase, demands for gas sensors are rapidly increasing. Among various gas sensor types, the semiconductor metal oxide (SMO)-type sensor has advantages of high sensitivity, low cost, mass production, and small size but suffers from poor selectivity. To solve this problem, electronic nose (e-nose) systems using a gas sensor array and pattern recognition are widely used.

Enhancement of Single-Photon Purity and Coherence of III-Nitride Quantum Dot with Polarization-Controlled Quasi-Resonant Excitation.

III-Nitride semiconductor-based quantum dots (QDs) play an essential role in solid-state quantum light sources because of their potential for room-temperature operation. However, undesired background emission from the surroundings deteriorates single-photon purity. Moreover, spectral diffusion causes inhomogeneous broadening and limits the applications of QDs in quantum photonic technologies.

Distinctive clinical features of spontaneous pneumoperitoneum in neonates: A retrospective analysis.

Background: Spontaneous pneumoperitoneum (SP) without gastrointestinal perforation rarely occurs in neonates, with most SP cases being idiopathic. Although SP usually follows a benign clinical course with favorable prognosis, it can become life-threatening in certain situations. In these cases, urgent surgical intervention may be required.

Influence of wafer quality on chip size-dependent efficiency variation in blue and green micro light-emitting diodes.

We propose a key factor associated with both surface recombination velocity and radiative efficiency of an LED to estimate its chip size-dependent radiative efficiencies. The validity of the suggested factor is verified through experimental comparison between various LED wafers. Efficiencies of micro-LEDs from a blue and two green LED wafers are examined by temperature-dependent photoluminescence experiments.

Spatially isolated neutral excitons clusters on trilayer MoS.

In spite of having a large exciton binding energy, two-dimensional (2D) transition metal dichalcogenides (TMDs) are limited as light-emitting materials because the spectral weight of neutral excitons decreases exponentially with increasing the excitation density. That is, neutral excitons easily transfer to trions, and exciton-exciton annihilation (EEA) occurs due to the strengthening of exciton kinetic energy in the layered structure. In here, we come up with an isolated neutral exciton system, maintaining its high spectral weight when the carrier density increased, which is achieved MoS clusters on a MoS trilayer directly synthesized by metal-organic chemical vapor deposition (MOCVD).

Wide-Field Super-Resolution Optical Fluctuation Imaging through Dynamic Near-Field Speckle Illumination.

Stochastic optical fluctuation imaging (SOFI) generates super-resolution fluorescence images by emphasizing the positions of fluorescent emitters via statistical analysis of their on-and-off blinking dynamics. In SOFI with speckle illumination (S-SOFI), the diffraction-limited grain size of the far-field speckles prevents independent blinking of closely located emitters, becoming a hurdle to realize the full super-resolution granted by SOFI processing. Here, we present a surface-sensitive super-resolution technique exploiting dynamic near-field speckle illumination to bring forth the full super-resolving power of SOFI without blinking fluorophores.

Surgical perspectives of symptomatic omphalomesenteric duct remnants: Differences between infancy and beyond.

Background: The clinical manifestations of omphalomesenteric duct remnant (OMDR) can vary with the age at diagnosis, from asymptomatic incidental findings to symptoms related to gastrointestinal complications. The lifelong complication rates are reported as 4%-34%, and complications are more common in patients younger than 2 years of age. The authors attempted to identify different clinical features and management for the various pediatric age groups.

Scrotal pyocele secondary to gastrointestinal perforation in infants: a case series.

Pyocele in infants is rarely described in the literature, but it is an emergent condition that requires rapid recognition and treatment to prevent testicular loss. If peritonitis due to gastrointestinal perforation occurs, abdominal contamination may spread through a patent processus vaginalis in an infant, which may lead to pyocele. We report the cases of three infants with scrotal pyocele due to the spread of infection or inflammatory material from the intraperitoneal cavity through a patent processus vaginalis.

Assessment of defecation function beyond infantile period for transanal single-stage endorectal pull-through in Hirschsprung disease.

Purpose: Transanal single-stage endorectal pull-through (TERPT) procedure for patients with Hirschsprung disease (HD) has favorable outcomes, with a lower complication rate. Nevertheless, various degrees of bowel dysfunction and fecal incontinence can persist for a long time in some patients. The aim of this study was to assess the mid- and long-term outcomes of TERPT performed during the infantile period after the completion of toilet training.

Experience with a Hybrid Procedure Involving Laparoscopic Fundoplication with Percutaneous Endoscopic Gastrostomy in Chronically Ill Children.

Gastrostomy with concurrent laparoscopic Nissen fundoplication (LNF) is often performed as a laparoscopic gastrostomy (LG) by surgeons. Since 2014, we started performing percutaneous endoscopic gastrostomy (PEG) as gastrostomy with LNF. This study aims to compare the outcomes of LG and PEG with LNF.

Correlation between Exposure to Fine Particulate Matter (PM2.5) during Pregnancy and Congenital Anomalies: Its Surgical Perspectives.

Background: Fine particulate matter (PM) can easily penetrate blood vessels and tissues through the human respiratory tract and cause various health problems. Some studies reported that particular matter (PM) exposure during pregnancy is associated with low birth weight or congenital cardiovascular anomalies. This study aimed to investigate the correlation between the degree of exposure to PM ≤ 2.

Highly Efficient Vacuum-Evaporated CsPbBr Perovskite Light-Emitting Diodes with an Electrical Conductivity Enhanced Polymer-Assisted Passivation Layer.

Highly efficient vacuum-deposited CsPbBr perovskite light-emitting diodes (PeLEDs) are demonstrated by introducing a separate polyethylene oxide (PEO) passivation layer. A CsPbBr film deposited on the PEO layer via thermal co-evaporation of CsBr and PbBr exhibits an almost 50-fold increase in photoluminescence quantum yield intensity compared to a reference sample without PEO. This enhancement is attributed to the passivation of interfacial defects of the perovskite, as evidenced by temperature-dependent photoluminescence measurements.

Nanoscale Focus Pinspot for High-Purity Quantum Emitters via Focused-Ion-Beam-Induced Luminescence Quenching.

Epitaxially grown quantum dots (QDs), especially embedded in photonic structures, play an essential role in various quantum photonic systems as on-demand single-photon sources. However, these QDs often suffer from adjacent unwanted emitters, which contribute to the background noise of the QD emission and fundamentally limit the single-photon purity. In this paper, a nanoscale focus pinspot (NFP) technique using focused-ion-beam-induced luminescence quenching enables us to improve single-photon purity from site-controlled QD as a proof-of-concept experiment.

Absent or impaired rectoanal inhibitory reflex as a diagnostic factor for high-grade (grade III-V) rectal prolapse: a retrospective study.

Background: Clinically diagnosing high-grade (III-V) rectal prolapse might be difficult, and the prolapse can often be overlooked. Even though defecography is the significant diagnostic tool for rectal prolapse, it is noticed that rectoanal inhibitory reflex (RAIR) can be associated with rectal prolapse. This study investigated whether RAIR can be used as a diagnostic factor for rectal prolapse.