Surface Plasmonics and Its Applications in Infrared Sensing

Surface plasmonic waves have been extensively researched due to their strong surface confinement. The strong surface confinement allows high absorption in an infrared (IR) detector with a thin active absorption region. The excitation of surface plasmonic resonance (SPR) depends on the metallic structures and the interface materials. This enables engineering of plasmonic-enhanced IR detector properties (e.g. detection wavelength, polarization and angular dependence) by properly designing the plasmonic structures. This chapter first gives a brief review of the surface plasmonic waves, followed by the description of SPR excitation in a metallic two-dimensional (2D) sub-wavelength hole array (2DSHA) structure. The applications of the 2DSHA SPR in IR detector enhancement are then presented with a discussion of the polarization and angular dependence

Voltage-Tunable Mid- and Long-Wavelength Dual-Band Infrared Photodetector Based on Hybrid Self-Assembled and Sub-Monolayer Quantum Dots

In this paper, we report a mid-wave infrared (MWIR) and long-wave infrared (LWIR) dual-band photodetector capable of voltage-controllable detection band selection. The voltage-tunable dual-band photodetector is based on the multiple stacks of sub-monolayer (SML) quantum dots (QDs) and self-assembled QDs. By changing the photodetector bias voltages, one can set the detection band to be MWIR, or LWIR or both with high photodetectivity and low crosstalk between the bands

Research on standardization construction of information interoperability framework

There are various ways for various services to carry out accusation information interoperability. The establishment of a standardized accusation information interoperability framework can provide a way to solve the problem of diversified and complicated implementation of accusation information interoperability between systems. This paper analyzes and compares three types of design methods, centering on the Battle Management Language(BML), combined with the structural concepts of Service-Oriented Architecture(SOA) and Unified Architecture Framework(UAF). Finally, a directly connected structural framework was chosen to build, and a public service supporting structural framework including six levels of system, technology, resources, service, function and organization, and multiple elements such as ontology model, semantic mapping and model generation is constructed, providing theoretical support for the research on standardization of accusative information interoperability

Relationship between Brain Natriuretic Peptide and Thromboembolic Events in Elderly Patients with Nonvalvular Atrial Fibrillation

Objective. To investigate the relationship between brain natriuretic peptide (BNP) and thromboembolic events in elderly patients with nonvalvular atrial fibrillation (NVAF). Methods. This is a prospective cohort study, and based on the inclusion and exclusion criteria, 180 elderly patients with NVAF were included. The patients received follow-up appointments in the clinic or by telephone every 6 months after the beginning of the study. The primary follow-up endpoints were thromboembolic and atherosclerotic events, including ischaemic stroke, myocardial infarction, and systemic embolism. The secondary endpoints were adverse events, including cardiovascular death, all-cause death, and hospitalisation for heart failure. Patients were divided into three groups according to their BNP level at admission: group A (BNP ≤334.5 pg/mL), group B (BNP = 334.5–1,288 pg/mL), and group C (BNP ≥1,288 pg/mL). Results. A total of 180 patients were enrolled in this study, with 50 patients in group A, 68 in group B, and 62 in group C. Compared with groups A and B, group C had a higher CHA2DS2-VASc score (Z = 15.142; P=0.001) and a lower ejection fraction (EF) value (Z = 119.893; P=0.001). The left atrium (LA) and left ventricular end-diastolic diameter (LVEDD) were larger (Z = 105.031; P=0.001 and Z = 74.430; P=0.001), respectively, suggesting that patients with significantly increased BNP had a higher risk of thromboembolism and atherosclerosis, lower EF, larger LA and LVEDD, and worse cardiac function. After 1 year of follow-up, the incidence of primary endpoint events (χ2 = 9.556; P=0.008) and secondary endpoint events (χ2 = 59.485; P=0.001) in group C were higher than those in groups A and B. Conclusion. Higher BNP levels may be an independent risk factor for thromboembolic and atherosclerotic events in elderly patients with NVAF. The higher the BNP level, the greater the risk of thromboembolic and atherosclerotic events

A modular industry-centered program for photonics and integrated photonics certification

© 2019 SPIE. Although demand for photonic technology is rapidly growing, there is a shortage of qualified workers to fill the industrial positions being created. At present, most photonics programs are available only at the graduate level; of the few undergraduate programs that exist, most are four-year engineering degrees. There is an unmet need for programs that can rapidly prepare students with minimal preparation to work as technicians in the optics and photonics industry. We report on a collaboration among Stonehill College, Bridgewater State University, and AIM Photonics Academy of MIT to create a unique photonics technician training and certification program that could serve as a template for other colleges or for other educational and manufacturing partnerships. This program, prepared with input from industry, consists of a mix of online, classroom, and lab courses (including both real-world and virtual experiments), with emphasis on hands-on experiences and apprenticeships with local companies. It is designed to rapidly develop practical skills in students who either have no prior technical background or who desire to quickly move into photonics from another technical area. The curriculum development model is modular, easily adapted across manufacturing sectors, focusing on skills sought by industry partners, with mechanisms in place for periodic feedback from employers. A clearinghouse for instructional materials will be created to house course outlines, syllabi, and teaching strategies for use by other institutions. Additionally, the curriculum will be sustained by making it stackable with other modules, training programs, and certifications aimed at other manufacturing specializations

Surface current confinement in circular ring optical antennas and its enhancement effect to the photoresponse of longwave infrared photodetectors

© 2018 IOP Publishing Ltd. In this paper, we report the analysis of surface current confinement in circular ring optical antennas and its enhancement effect to the photoresponse of quantum dot (QD) longwave infrared (LWIR) photodetectors. Circular ring optical antennas with various inner and outer diameters were simulated to determine the electric near-field (E-field) and surface current distribution. Over 80 times E-field enhancement was obtained when the width of the ring is as narrow as 2 nanometers (nm) where the surface current is strongly confined. In addition, the E-field (|E|) shows a direct linear relationship with the surface current density. The linear relationship is analyzed using an RLC circuit model. The E-field enhancement of the circular ring optical antenna is compared with that of the two-dimensional metallic subwavelength hole arrays structure (2DSHA) and is found to have higher enhancement with a broader spectral band coverage. The circular ring optical antenna enhanced LWIR QD infrared photodetectors were fabricated and measured. The ring optical antenna with stronger surface current confinement shows a higher photocurrent enhancement. The experimental results agree well with the simulation. Broader band photocurrent enhancement than the 2DSHA structure was also verified

Study of frequency-dependent plasmonic enhancement of a circular disk nano-optical antenna array using a femtosecond laser frequency comb

© 2019 IOP Publishing Ltd. In this paper, we report the study of the frequency-dependent plasmonic enhancement of a circular disk nano-optical antenna array and the photo-response of the optical antenna enhanced photodetector at different frequencies using a femtosecond (fs) laser frequency comb. A fs-laser frequency comb can provide hundreds of evenly spaced harmonic frequencies and thus allows simultaneous measurement of the plasmonic optical antenna enhancement effect at these harmonic frequencies. This offers a highly efficient frequency-dependent measurement approach compared to the conventional method of modulating of a c.w. laser, which measures the frequency response at each frequency. The impulse response of the circular disk nano-optical antenna array and the electric-field (E-field) distribution profile are simulated under a fs laser illumination. The light intensity spectrum is simulated and verified to have uniform intensities on the harmonic frequencies within the ±5 GHz frequency range. The photocurrent densities in different regions of a GaAs p-i-n photodetector are analyzed together with their frequency dependence at the harmonic frequencies of the fs laser frequency comb with a repetition rate of MHz. A circular disk nano-optical antenna array enhanced GaAs p-i-n photodetector was fabricated and measured using a fs laser frequency comb with the same repetition rate. The nano-optical antenna can provide ∼20 dB enhancement for the harmonic frequencies and extend the detector cut-off frequency from 2.4 GHz to 4.2 GHz

All-Printed Thin-Film Transistor Based on Purified Single-Walled Carbon Nanotubes with Linear Response

We report an all-printed thin-film transistor (TFT) on a polyimide substrate with linear transconductance response. The TFT is based on our purified single-walled carbon nanotube (SWCNT) solution that is primarily consists of semiconducting carbon nanotubes (CNTs) with low metal impurities. The all-printed TFT exhibits a high ON/OFF ratio of around 103 and bias-independent transconductance over a certain gate bias range. Such bias-independent transconductance property is different from that of conventional metal-oxide-semiconductor field-effect transistors (MOSFETs) due to the special band structure and the one-dimensional (1D) quantum confined density of state (DOS) of CNTs. The bias-independent transconductance promises modulation linearity for analog electronics