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CMOS image sensor (CIS) plays a crucial role in diverse optical applications by facilitating the capture of images in the visible and near-infrared spectra. The enhancement of image resolution in CIS by an increase in pixel density is becoming more significant and realizable with the recent progress of nanofabrication. However, as pixel size decreases towards the diffraction limit, there is an inevitable trade-off between the scale-down of pixel size and the enhancement of optical sensitivity. Recently, to overcome this, an entirely new concept of spectral sensing using a nanophotonic-based color router has been proposed. In this work, we present a metasurface-based spectral router to effectively split the spectrum from visible to near-infrared and redirect through the four optical channels to the targeted pixel surfaces. We optimize the metasurface that simultaneously controls the phases of the transmitted light of targeted spectra, i.e. red (R), green (G), blue (B), and near-infrared (NIR), which is the largest number of channels reported based on a single layered metasurface and has an optical efficiency that surpasses the efficiency of conventional color filter systems.

Silicon (Si) offers cost-effective production and convenient on-chip integration for photodetection due to its well-established CMOS technology. However, the indirect bandgap of Si inherently limits its detection efficiency in the near-infrared (NIR) regime. Here, we propose a strategy to achieve high NIR photoresponse in Si by introducing a strong light-absorbing ultrathin gold (Au) film to generate hot carriers. Using a 4.6 nm thick-Au film deposited on Si, we achieved photoresponsivity of 1.6 mA/W at 1310 nm under zero-bias conditions, and rapid temporal responses of 7.5 and 8 μs for rise and fall times, respectively, comparable to germanium (Ge) photodiodes. By utilizing an ultrathin (100 nm) Au film as electrodes, we introduce a unique approach to design a photodiode array based on a single metal (Au) platform. Comparative analysis with a commercial beam profiler image validates the performance of our designed array. This work presents an efficient strategy for manufacturing cost-effective and scalable NIR photodetector arrays, which eliminates the need for additional insulator layers.

ObjectivesTo assess the feasibility of a CNN-based liver registration algorithm to generate difference maps for visual display of spatiotemporal changes in liver PDFF, without needing manual annotations.MethodsThis retrospective exploratory study included 25 patients with suspected or confirmed NAFLD, who underwent PDFF-MRI at two time points at our institution. PDFF difference maps were generated by applying a CNN-based liver registration algorithm, then subtracting follow-up from baseline PDFF maps. The difference maps were post-processed by smoothing (5 cm2 round kernel) and applying a categorical color scale. Two fellowship-trained abdominal radiologists and one radiology resident independently reviewed difference maps to visually determine segmental PDFF change. Their visual assessment was compared with manual ROI-based measurements of each Couinaud segment and whole liver PDFF using intraclass correlation (ICC) and Bland-Altman analysis. Inter-reader agreement for visual assessment was calculated (ICC).ResultsThe mean patient age was 49 years (12 males). Baseline and follow-up PDFF ranged from 2.0 to 35.3% and 3.5 to 32.0%, respectively. PDFF changes ranged from - 20.4 to 14.1%. ICCs against the manual reference exceeded 0.95 for each reader, except for segment 2 (2 readers ICC = 0.86-0.91) and segment 4a (reader 3 ICC = 0.94). Bland-Altman limits of agreement were within 5% across all three readers. Inter-reader agreement for visually assessed PDFF change (whole liver and segmental) was excellent (ICCs > 0.96), except for segment 2 (ICC = 0.93).ConclusionsVisual assessment of liver segmental PDFF changes using a CNN-generated difference map strongly agreed with manual estimates performed by an expert reader and yielded high inter-reader agreement.Key points• Visual assessment of longitudinal changes in quantitative liver MRI can be performed using a CNN-generated difference map and yields strong agreement with manual estimates performed by expert readers.

This study investigates phonological characteristics of Korean monolingual children with phonological disorders (PD), using data from 13 children aged 3.6 to 5.9, and compares the analyses of single-word productions (SW) to those of conversational speech (CS). Phonological analyses include overall percentage of consonants correct (PCC), individual phoneme accuracy, and phonological error patterns. Results indicate that children with PD have persistent difficulty with affricates, fricatives, and the liquid /l/. Overall consonant accuracy tends to be greater in CS than SW. Phonological errors that may be explained by language-specific phonological and phonetic properties of Korean are noted.

The purpose of this study is to evaluate the changes in the palatal alveolar bone thickness and find the factors related to the resorption of the palatal alveolar bone caused by tooth movement after the maxillary incisors were retracted and intruded during orthodontic treatment. The study group comprised of 33 skeletal Class II malocclusion patients who underwent extraction for orthodontic treatment. Palatal alveolar bone thickness changes and resorption factors were identified and analyzed. The changes of maxillary central incisors and palatal alveolar bone thickness were measured, and the corresponding sample t test was performed using SPSS (IBM SPSS version 22). The amount of palatal alveolar bone resorption was measured and various parameters were analyzed to determine which factors affected it. Correlation analysis adopting the amount of palatal alveolar bone resorption as a dependent variable demonstrated that the SNB, mandibular plane angle, and the inclination of the maxillary central incisor were significantly correlated with before treatment. On the other hand, mandibular plane angle, angle of convexity, the inclination of the upper incisor, and the occlusal plane (UOP, POP) were significantly correlated with post-treatment. In addition, the variables related to palatal contour (PP to PAS, SN to PAS, palatal surface angle) and occlusal planes (UOP/POP) were significantly correlated with the difference in palatal bone resorption. During initial diagnosis, high angle class II with normal upper incisor inclination can be signs of high-risk factors. In addition, maintaining the occlusal plane during treatment helps to prevent palatal bone loss.

The ability of modulating optical properties at a lateral subwavelength scale is of crucial importance due to its potential applications for wide-angle holographic displays, optical communications, and interferometric sensors. Here, we present an electrically tunable metasurface whose optical properties can be element-wise controlled at the lateral subwavelength scale in the mid-infrared wavelength regime. Our proposed device facilitates an n-doped InAs layer as a dynamic-tunable layer, and the charge carrier concentration inside the InAs layer is tailored by external gate biases. This InAs active layer is sandwiched between top aluminum strip antennas and a bottom gold substrate, forming the metal–insulator–metal configuration. The change of the charge carrier concentration gives rise to modulation of the amplitude and phase of reflected light in a mid-infrared regime. Numerical investigations show the reflectivity contrast of 44%P with biases of −2.5–0 V and the phase change of 236° with biases of −15 V to +15 V at the wavelength of ∼5 μm. Versatile wavefront shaping such as beam focusing with Fresnel Zone plate and beam steering with saw-tooth phase grating is also provided.