More Like this

1. Rapid Surface Charge Mapping Based on a Liquid Crystal Microchip

   https://doi.org/10.3390/bios14040199  

   Ouyang, Leixin; Chen, Heyi; Xu, Ruiting; Shaik, Rubia; Zhang, Ge; Zhe, Jiang (April 2024, Biosensors)

   Rapid surface charge mapping of a solid surface remains a challenge. In this study, we present a novel microchip based on liquid crystals for assessing the surface charge distribution of a planar or soft surface. This chip enables rapid measurements of the local surface charge distribution of a charged surface. The chip consists of a micropillar array fabricated on a transparent indium tin oxide substrate, while the liquid crystal is used to fill in the gaps between the micropillar structures. When an object is placed on top of the chip, the local surface charge (or zeta potential) influences the orientation of the liquid crystal molecules, resulting in changes in the magnitude of transmitted light. By measuring the intensity of the transmitted light, the distribution of the surface charge can be accurately quantified. We calibrated the chip in a three-electrode configuration and demonstrated the validity of the chip for rapid surface charge mapping using a borosilicate glass slide. This chip offers noninvasive, rapid mapping of surface charges on charged surfaces, with no need for physical or chemical modifications, and has broad potential applications in biomedical research and advanced material design. 

   more » « less
2. Topological on-chip lasers

   https://doi.org/10.1063/5.0150421  

   Li, Zhitong; Luo, Xi-Wang; Gu, Qing (July 2023, APL Photonics)

   A miniature on-chip laser is an essential component of photonic integrated circuits for a plethora of applications, including optical communication and quantum information processing. However, the contradicting requirements of small footprint, robustness, single-mode operation, and high output power have led to a multi-decade search for the optimal on-chip laser design. During this search, topological phases of matter—conceived initially in electronic materials in condensed matter physics—were successfully extended to photonics and applied to miniature laser designs. Benefiting from the topological protection, a topological edge mode laser can emit more efficiently and more robustly than one emitting from a trivial bulk mode. In addition, single-mode operation over a large range of excitation energies can be achieved by strategically manipulating topological modes in a laser cavity. In this Perspective, we discuss the recent progress of topological on-chip lasers and an outlook on future research directions. 

   more » « less
3. On-chip terahertz orbital angular momentum demultiplexer

   https://doi.org/10.1364/PRJ.519701  

   Jiang, Xiaohan; Liu, Wanying; Xu, Quan; Lang, Yuanhao; Fu, Yikai; Huang, Fan; Dai, Haitao; Li, Yanfeng; Zhang, Xueqian; Gu, Jianqiang; et al (May 2024, Photonics Research)

   The terahertz regime is widely recognized as a fundamental domain with significant potential to address the demands of next-generation wireless communications. In parallel, mode division multiplexing based on orbital angular momentum (OAM) shows promise in enhancing bandwidth utilization, thereby expanding the overall communication channel capacity. In this study, we present both theoretical and experimental demonstrations of an on-chip terahertz OAM demultiplexer. This device effectively couples and steers seven incident terahertz vortex beams into distinct high-quality focusing surface plasmonic beams, and the focusing directions can be arbitrarily designated. The proposed design strategy integrates space-to-chip mode conversion, OAM recognition, and on-chip routing in a compact space with subwavelength thickness, exhibiting versatility and superior performance. 

   more » « less
4. 3SAT on an all-to-all-connected CMOS Ising solver chip

   https://doi.org/10.1038/s41598-024-60316-y  

   Cılasun, Hüsrev; Zeng, Ziqing; S, Ramprasath; Kumar, Abhimanyu; Lo, Hao; Cho, William; Moy, William; Kim, Chris H.; Karpuzcu, Ulya R.; Sapatnekar, Sachin S. (May 2024, Scientific Reports)

   Abstract This work solves 3SAT, a classical NP-complete problem, on a CMOS-based Ising hardware chip with all-to-all connectivity. The paper addresses practical issues in going from algorithms to hardware. It considers several degrees of freedom in mapping the 3SAT problem to the chip—using multiple Ising formulations for 3SAT; exploring multiple strategies for decomposing large problems into subproblems that can be accommodated on the Ising chip; and executing a sequence of these subproblems on CMOS hardware to obtain the solution to the larger problem. These are evaluated within a software framework, and the results are used to identify the most promising formulations and decomposition techniques. These best approaches are then mapped to the all-to-all hardware, and the performance of 3SAT is evaluated on the chip. Experimental data shows that the deployed decomposition and mapping strategies impact SAT solution quality: without our methods, the CMOS hardware cannot achieve 3SAT solutions on SATLIB benchmarks. Under the assumption of some hardware improvements, our chip-based 3SAT solver demonstrates a remarkable 250$$\times$$ $\times$acceleration compared to Tabu search in dwave-hybrid on a CPU. 

   more » « less
5. III/V silicon hybrid laser based on a resonant Bragg structure

   https://doi.org/10.1364/AO.390522  

   Davis, Jordan_A; Kim, Myun_Sik; El_Amili, Abdelkrim; Trotter, Douglas_C; Starbuck, Andrew_L; Dallo, Christina; Pomerene, Andrew_T; DeRose, Christopher_T; Lentine, Anthony_L; Fainman, Yeshaiahu (May 2020, Applied Optics)

   We demonstrate a laser tunable in intensity with gigahertz tuning speed based on a III/V reflective semiconductor optical amplifier (RSOA) coupled to a silicon photonic chip. The silicon chip contains a Bragg-based Fabry–Perot resonator to form a passive bandpass filter within its stopband to enable single-mode operation of the laser. We observe a side mode suppression ratio of 43 dB, linewidth of 790 kHz, and an optical output power of 1.65 mW around 1530 nm. We also investigate using a micro-ball lens as an alternative coupling method between the RSOA and the silicon chip. 

   more » « less