Growth of quantum three-dimensional structure of InGaAs emitting at ~1 µm applicable for a broadband near-infrared light source

We obtained a high-intensity and broadband emission centered at ~1 µm from InGaAs quantum three-dimensional (3D) structures grown on a GaAs substrate using molecular beam epitaxy. An InGaAs thin layer grown on GaAs with a thickness close to the critical layer thickness is normally affected by strain as a result of the lattice mismatch and introduced misfit dislocations. However, under certain growth conditions for the In concentration and growth temperature, the growth mode of the InGaAs layer can be transformed from two-dimensional to 3D growth. We found the optimal conditions to obtain a broadband emission from 3D structures with a high intensity and controlled center wavelength at ~1 µm. This method offers an alternative approach for fabricating a broadband near-infrared light source for telecommunication and medical imaging systems such as for optical coherence tomography

Large-Area Resonance-Tuned Metasurfaces for On-Demand Enhanced Spectroscopy

We show an effective procedure for lateral structure tuning in nanoimprint lithography (NIL) that has been developed as a vertical top-down method fabricating large-area nanopatterns. The procedure was applied to optical resonance tuning in stacked complementary (SC) metasurfaces based on silicon-on-insulator (SOI) substrates and was found to realize structure tuning at nm precision using only one mold in the NIL process. The structure tuning enabled us to obtain fine tuning of the optical resonances, offering cost-effective, high-throughput, and high-precision nanofabrication. We also demonstrate that the tuned optical resonances selectively and significantly enhance fluorescence (FL) of dye molecules in a near-infrared range. FL intensity on a SC metasurface was found to be more than 450-fold larger than the FL intensity on flat Au film on base SOI substrate

OCT with a Visible Broadband Light Source Applied to High-Resolution Nondestructive Inspection for Semiconductor Optical Devices

Optical coherence tomography with a visible broadband light source (vis-OCT) was developed for high-resolution and nondestructive measurements of semiconductor optical devices. Although a near-infrared (NIR) light source should be used for medical OCT to obtain deep penetration of biological samples, a visible broadband light source is available as a low-coherence light source for industrial products. Vis-OCT provides higher axial resolution than NIR-OCT, because the axial resolution of an OCT image is proportional to the square of the center wavelength of the light source. We developed vis-OCT with an axial resolution of less than 1 μm in air and obtained cross-sectional profiles and images of ridge-type waveguides having heights and widths of several μm. Additionally, we performed cross-sectional measurements and imaging of a stacked semiconductor thin layer. The measured values were similar to those measured by scanning electron microscopy, and the effectiveness of vis-OCT for nondestructive inspection of semiconductor optical devices was demonstrated

Development of a broadband superluminescent diode based on self-assembled InAs quantum dots and demonstration of high-axial-resolution optical coherence tomography imaging

We developed a near-infrared (NIR) superluminescent diode (SLD) based on self-assembled InAs quantum dots (QDs) and demonstrated high-axial-resolution optical coherence tomography (OCT) imaging using this QD-based SLD (QD-SLD). The QD-SLD utilized InAs QDs with controlled emission wavelengths as a NIR broadband light emitter, and a tilted waveguide with segmented electrodes was prepared for edge-emitting broadband electroluminescence (EL) spanning approximately 1–1.3 μm. The bandwidth of the EL spectrum was increased up to 144 nm at a temperature of 25 °C controlled using a thermoelectric cooler. The inverse Fourier transform of the EL spectrum predicted a minimum resolution of 3.6 μm in air. The QD-SLD was subsequently introduced into a spectral-domain (SD)-OCT setup, and SD-OCT imaging was performed for industrial and biological test samples. The OCT images obtained using the QD-SLD showed an axial resolution of ~4 μm, which was almost the same as that predicted from the spectrum. This axial resolution is less than the typical size of a single biological cell (~5 μm), and the practical demonstration of high-axial-resolution OCT imaging shows the application of QD-SLDs as a compact OCT light source, which enables the development of a portable OCT system

Age-specific serum anti-Müllerian hormone concentration in Japanese women and its usefulness as a predictor of the ovarian response

Purpose: To compare the ovarian response predictive ability of anti-Müllerian hormone (AMH), follicle-stimulating hormone (FSH), and estradiol (E2) and to determine the age-specific distribution of serum AMH concentrations of Japanese women. Methods: This was a multicenter (four-site), observational, analytic, cross-sectional Japanese study consisting of two parts: Study 1 (the prediction of the ovarian response of 236 participants who were undergoing controlled ovarian stimulation [COS]) and Study 2 (the distribution of the AMH concentration with an assay of 417 healthy women who were aged 20-49 years and who had normal menstrual cycles). Results: The AMH had a significantly higher predictive value for the normal and high responders than FSH and E2 as a stronger correlation between the ovarian response and AMH was observed than for FSH and E2. The serum AMH concentration decreased proportionally with age. Conclusion: The AMH concentration correlated well with the oocyte count in the patients who were undergoing COS for in vitro fertilization and was shown to predict the risk of ovarian hyperstimulation syndrome among these patients

Continuous in-vIvo measurement of the brain tissue and the ischemic muscle gas tension using MEDSPECT, MS-8

I MEDSPECT is a medical mass spectrometer for continuous in-vivo measurement of tissue, blood and respiratory gases. Interfacing catheter for tissue in measurement has Teflon membrane. The permeability and perfusion rate for various gases through its membrane varied with temperature. The temperature coefficient of Teflon catheter in the range of 15℃-40℃ is approximately constant with -2% of correction per degree for oxygen and carbon dioxide. Linear correlation was confirmed experimentally. II The brain tissue gas tensions were measured in ten dogs with intra-venous anesthesia at normothermia and deep hypothermia using perfusion cooling, including circulatory arrest for 30 minutes at 20°C of cerebral temperature. On average, the brain tissue P(O2) was 15mmHg in normothermia when the arterial P(O2) showed 95mmHg and the brain tissue P(CO2) was 49mmHg when the arterial PC02 showed 30mmHg. The brain tissue carbon dioxide tension gradually decreased by cooling and increased during circulatory arrest for 30 minutes; from 45mmHg to 72mmHg. The brain tissue oxygen tension increased during cooling from 15mmHg to 41mmHg and decreased in the circulatory arrest; from 41mmHg to 36mmHg. III The ischemic muscle gas tension was measured in a 22-year-old man, who was suffered from thromboangiitis obliterans bilaterally, and had the popliteal autovein bypass surgery 3 months ago. Control oxygen tensions in the both anterior tibial muscles showed about the same; 35mmHg and 36mmHg respectivelly, and the P(O2) of the non-operated side showed remarkable low level of 18mmHg as compared with the side of arterial reconstruction surgery after 5-minutes ankle exercise