Orbital Angular Momentum Mode Multiplexer Based on Multimode Micro-Ring Resonator with Angular Gratings

We demonstrate silicon photonic orbital angular momentum multiplexing devices based on mulitmode microring resonator. Up to four optical beams carrying different orbital angular momentum states can be selectively excited from different input ports

Modeling Human Performance on Statistical Word Segmentation Tasks

Harnessing the orbital angular momentum (OAM) of light is an appealing approach to developing photonic technologies for future applications in optical communications and high-dimensional quantum key distribution (QKD) systems. An outstanding challenge to the widespread uptake of the OAM resource is its efficient generation. In this work we design a new device that can directly emit an OAM-carrying light beam from a low-cost semiconductor laser. By fabricating micro-scale spiral phase plates within the aperture of a vertical-cavity surface-emitting laser (VCSEL), the linearly polarized Gaussian beam emitted by the VCSEL is converted into a beam carrying specific OAM modes and their superposition states, with high efficiency and high beam quality. This new approach to OAM generation may be particularly useful in the field of OAM-based optical and quantum communications, especially for short-reach data interconnects and QKD

Effect of albumin administration on post-operation mortality, duration on ventilator, and hospital stay on patients in cardiac intensive care: An observational study

Purpose: To justify the use of albumin infusion in patients in post-surgery cardiac intensive care unit. Methods: All patients who were hemodynamically stable before the operation and admitted into the surgical intensive care unit following coronary artery bypass, cardiopulmonary bypass, or aortic surgery, had no excessive postoperative bleeding and not on diuretic treatment, were included in the analysis. A total of 1998 patients were divided into two cohorts, viz, the first group was placed on albumin infusion (n = 999) while the second group received normal saline infusion (n = 999). Data were obtained from DICOM files of patients and records of pharmacy. Wilcoxon test or two-tailed paired t-test followed by Tukey post-hoc tests were performed for statistical analysis at 95 % of confidence level. Results: Albumin and normal saline administration did not decrease the duration of mechanical ventilation, incidence of mechanical ventilation, need for blood transfusion, and length of hospital stay (p > 0.05). Albumin infusion decreased the need for fresh frozen plasma transfusion from 85 to 67, reduced mortality (p = 0.0005, q = 3.959), lowered serum lactate level (p < 0.0001, q = 43.853), but increased cardiac index (p < 0.0001, q = 12.192) as well as financial burden (p < 0.0001, q = 95.158) for the patients, compared to normal saline group. Conclusion: In view of the foregoing, it is recommended that the use of restriction of albumin resuscitation in surgical intensive care unit should be restricted in this subset of patients evluated in this study

Experimental Observation of Optical Bistability in an Integrated Vortex Beam Emitter

We experimentally demonstrate an interesting phenomenon of optical bistability in an integrated optical vortex emitter when injecting high power into the waveguide due to the nonlinear optical effects. We clearly observe a hysteresis loop of the radiation power from the integrated vortex beam emitter when increasing and decreasing the input power

Preparation and imaging of intravascular high-frequency transducer

Intravascular ultrasound (IVUS) imaging is by far the most favorable imaging modality for coronary artery evaluation. IVUS transducer design and fabrication, a key technology for intravascular ultrasound imaging, has a significant impact on the performance of the imaging results. Herein, a 35-MHz side-looking IVUS transducer probe was developed. With a small aperture of 0.40 mm × 0.40 mm, the transducer exhibited a very wide -6 dB bandwidth of 85% and a very low insertion loss of -12 dB. Further, the in vitro IVUS imaging of a porcine coronary artery was performed to clearly display the vessel wall structure while the corresponding color-coded graph was constructed successfully to distinguish necrotic core and fibrous plaque via image processing. The results demonstrated that the imaging performance of the optimized design transducer performs favorably

Generation of photonic orbital angular momentum superposition states using vortex beam emitters with superimposed gratings

An integrated approach to produce photonic orbital angular momentum (OAM) superposition states with arbitrary OAM spectrum has been demonstrated. Superposition states between two vector OAM modes have been achieved by integrating a superimposed angular grating in one silicon micro-ring resonator, with each mode having near equal weight. The topological charge difference between the two compositional OAM modes is determined by the difference between the numbers of elements in the two original gratings being superimposed, while the absolute values of the topological charge can be changed synchronously by switching WGM resonant wavelengths. This novel approach provides a scalable and flexible source for the OAM-based quantum information and optical manipulation applications

Pattern manipulation via on-chip phase modulation between orbital angular momentum beams

An integrated approach to thermal modulation of relative phase between two optical vortices with opposite chirality has been demonstrated on a silicon-on-insulator substrate. The device consists of a silicon-integrated optical vortex emitter and a phase controlled 3 dB coupler. The relative phase between two optical vortices can be actively modulated on chip by applying a voltage on the integrated heater. The phase shift is shown to be linearly proportional to applied electrical power, and the rotation angle of the interference pattern is observed to be inversely proportional to topological charge. This scheme can be used in lab-on-chip, communications and sensing applications. It can be intentionally implemented with other modulation elements to achieve more complicated applications