ABSTRACT
Bimetallic surface plasmon resonance (SPR) sensors have the potential to overcome the drawbacks of individual metals, but the effect of the configuration of the two metallic layers on the performance of the sensors has not been explored. This study examines the influence of different positions of a thin layer of silver in relation to a copper layer on the sensitivity of such a bimetallic SPR sensor. The design of this configuration aims to improve the SPR reflectance curve and strengthen the evanescent electric field to improve the sensor efficiency. Our findings indicate that, by optimizing the architectures of SPR sensors and using a silver-copper bimetallic structure, we can achieve superior performance compared to devices that utilize only silver or copper. The optimized Ag (5 nm)/Cu (55 nm) sensor design, with the best sensitivity of 299.09° RIU-1, can detect a change of 0.43°/(g dl-1) for hemoglobin in blood, 0.35°/(g dl-1) for glucose in urine, and 0.1°/(%) for methanol in ethanol. We also demonstrate the importance of signal quality by introducing two new parameters that offer a better quantitative indication of the efficiency of a sensor than is obtained by using only sensitivity.
ABSTRACT
In this paper, we propose a new device architecture for an all-optical logic inverter (NOT gate), which is cascadable with a similar device. The inverter is based on stimulated Raman scattering in silicon nanocrystal waveguides, which are embedded in a silicon photonic crystal structure. The Raman response function of silicon nanocrystal is evaluated to explore the transfer characteristic of the inverter. A maximum product criterion for the noise margin is taken to analyze the cascadability of the inverter. The time domain response of the inverter, which explores successful inversion operation at 100 Gb/s, is analyzed. Propagation delay of the inverter is on the order of 5 ps, which is less than the delay in most of the electronic logic families as of today. Overall dimension of the device is around 755 µm ×15 µm, which ensures integration compatibility with the matured silicon industry.
ABSTRACT
In this Letter, we propose an all-optical circuit for a cascadable and integrable logic inverter based on stimulated Raman scattering. A maximum product criteria for noise margin is taken to analyze the cascadability of the inverter. Variation of noise margin for different model parameters is also studied. Finally, the time domain response of the inverter is analyzed for different widths of input pulses.
