Shanghai Advanced Research Institute

RE-Ba-Cu-O (REBCO) bulk high temperature superconducting undulators have been experimentally demonstrated to generate undulator fields exceeding 2 T at a 10 mm period, outperforming alternative undulator technologies for short-period applications. This study aims to further enhance undulator performance by reducing the period length through optimization of staggered-array, half-moon-shaped REBCO bulks. We propose a novel dual-lunate-ring-based REBCO undulator geometry that enables control of magnetization currents within individual lunate rings. The coexistence of magnetization currents on both the upper and lower sides of the undulator axis contributes to a significant enhancement of the on-axis magnetic field. To evaluate the performance of this design, the undulator period and gap were fixed at 7 mm and 3.3 mm, respectively, while the dimensions of the bulk rings were optimized numerically using the H-formulation. When the background solenoidal field changes from 10T to zero (ΔBs = 10 T), the undulator is expected to achieve a field strength B0 of 1.65T with a 7 mm period, corresponding to a deflection parameter of K = 1.1.

Liquid crystal on silicon (LCoS) micro-display systems require compact and energy-efficient on-chip clock sources to ensure precise timing for display drivers and communication interfaces. This letter presents a process-resilient relaxation oscillator fabricated in a 0.18-<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mu$</tex-math></inline-formula>m CMOS process. To address the frequency instability caused by comparator non-idealities, the proposed design synergizes a time-domain chopping technique with a voltage averaging feedback (VAF) loop. This dual-mechanism effectively mitigates the impact of comparator input offset while automatically compensating for circuit delays. Measurement results demonstrate a fundamental frequency of 50 MHz with a power consumption of 122.1 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mu$</tex-math></inline-formula>W at 1.8 V supply, achieving an energy efficiency of 2.44 nW/kHz; the proposed design reduces the frequency standard deviation (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\sigma$</tex-math></inline-formula>) by 90.84%, and the duty cycle standard deviation (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\sigma$</tex-math></inline-formula>) by 95.47% compared to the conventional architecture, making it a robust clocking solution for LCoS applications.

Achieving uniform self-assembled monolayer (SAM) deposition on nickel oxide (NiOx) and suppressing interfacial defects caused by high-oxidation-state nickel species remains a challenge for inverted perovskite solar cells (PSCs). Here, we develop a surface modification strategy using cesium oxalate (CsOA) to synergistically regulate the NiOx/SAM buried interface. The CsOA treatment suppresses detrimental Ni4+ content and chelates with Ni3+ to form the complex [Ni(C2O4)3]3-, which maintains a stable oxidation state of Ni3+ and inhibits its continuing redox reactions as a result of the enhanced conductivity and p-type characteristics. Moreover, as a buffer layer, CsOA can prevent high-oxidation-state nickel species (Ni≥3+) from reacting directly with the perovskite in uncovered regions and passivate buried perovskite defects through the interaction of the oxalate ion and under-coordinated Pb2+. Additionally, the enhanced anchoring between SAM and NiOx/CsOA promotes uniform SAM assembly, thereby improving film quality and stability. As a result, the optimized NiOx/CsOA/SAM HTL enables inverted PSCs with efficiencies of 22.89% (1.67eV) and 26.48% (1.54eV), retaining 85.7% of the initial efficiency after 1560h under AM1.5G illumination at 65°C. A scalable mini-module (an active area of 11.0cm2) achieves an efficiency of 23.45%, highlighting the approach's potential for high-performance, stable, and industrially viable PSCs.