Multifunctional metasurfaces integrating near-field display and 3D holography

Metasurfaces have versatile manipulation capabilities in the optical field and provide the possibility of building a compact optical device with various complex functions. They have been regarded as ideal candidates to construct a miniaturized optical system with high density and multi-channel information. In this work, reflective all-metallic multifunctional metasurfaces consisting of aluminum nanorods are designed by simultaneously realizing the near-filed display and three-dimensional (3D) holography. Specifically, in the proposed design, each nanorod acts as a complex amplitude modulator to provide continuous amplitude control and binary phase control. By carefully optimizing the orientations of nanorods, a multifunctional metasurface can be designed to display a near-field grayscale pattern and far-field 3D images simultaneously. Numerical results by a full-wave simulation validate the good performance of the proposed design. The proposed method could provide more degree of freedom to designs of lightweight devices, which could be employed in optical applications, such as the virtual or augmented reality display and anti-counterfeit technology.

Amplitude modulator of Multi-walled Carbon nanotubes/Chitin in the C-band region

In ultrafast all-optical signal processing, the all-optical method is crucial, and all-fiber technique offers a wide range of applications in optical communications. This study investigated the amplitude modulation using multi-walled carbon nanotubes (MWCNTs) embedded into chitin as saturable absorber (SA). The MWCNTs-chitin SA is fabricate using a liquid phase exfoliation method to reduce complexity and produce an excellent material quality. In this paper, an optical amplitude modulator produced a linear region with a regression line of the peak intensity at pump power range from 17.92 mW to 67.92 mW with modulation efficiency of 0.50 dB/mW.

An Efficient Architecture for Accurate and Low Power CMOS Analog Multiplier

A new analog four-quadrant multiplier in CMOS technology is proposed using translinear loops (TLs). The novelty of the work includes an improved structure resulting in high precision output, low power consumption and low body effect error. The higher accuracy is achieved using a symmetrical arrangement of the proposed multiplier, where the errors on the two sides of circuit are subtracted from each other. The simple structure, as well as the sharing bias branch in the squaring circuits, leads to the low power dissipation of the multiplier circuit. In addition, the proposed circuit is thoroughly analyzed in terms of the body effect error and the results are presented. In order to validate the performance of the circuit, the designed multiplier is used in two useful applications: frequency doubler and amplitude modulator. The post layout simulation results of the circuit are performed using Cadence Virtuoso and HSPICE with level 49 parameters (BSIM3v3) of TSMC 0.18[Formula: see text][Formula: see text]m technology. The results show a nonlinearity of 0.93%, a total harmonic distortion (THD) of 0.98% at a frequency of 1[Formula: see text]MHz, a [Formula: see text]3[Formula: see text]dB bandwidth of 736[Formula: see text]MHz and a maximum power dissipation of 0.0619[Formula: see text]mW.

Performance of MIMO FBMC-OQAM and MIMO OFDM-QAM under time Synchronization Errors in Perfect CSI and Imperfect CSI

The requirement of flexible allocation of available limited frequency resources led to rethink the possibilities to find an substitute to Orthogonal Frequency Division Multiplexing (OFDM) [1], which can also meet the necessities of future wireless communication. In this paper, we have compared one such alternative to OFDM, which is Filter Bank Multi Carrier (FBMC) [2] with Offset Quadrature Amplitude Modulator (OQAM) . The BER performance of OQAM based MIMO FBMC compared with QAM based MIMO OFDM for various channels conditions and using different prototype filters [3] for FBMC and under the influence of Timing Offset errors with perfect CSI and imperfect CSI. Implementation of MIMO into OQAM-FBMC has a computational complexity compared to MIMO OFDM and we have used block coded MIMO OQAMFBMC for simulation. Three prototype filters RRC, Hermite and PHYDYAS are used to analyze the performance of OQAMFBMC in relations of Signal to Interference Ratio under time offset and found that performance of PHYDYAS prototype filter outperforms RRC and Hermite prototype filters.