物理与天体物理最新文献

Unidirectional electromagnetic modes, as an extreme regime of wave propagation, enable extraordinary and counterintuitive optical effects. These modes are typically realized as tightly confined surface waves in photonic crystals or materials with topologically nontrivial bandgaps. Here, we show that a structure comprising a magnetized semiconductor layer sandwiched between electro- and magneto-opaque materials can support unidirectional bulk magnetoplasmons at terahertz frequencies, in which all field components maintain constant amplitudes within the core layer. These modes exhibit modal properties that are independent of the core thickness, allowing the modal spot to extend over several wavelengths. Numerical simulations further confirm their immunity to backscattering. By combining the tunability of modal spot with the robustness of unidirectional propagation, these unidirectional bulk modes offer more degrees of freedom for the manipulation of terahertz waves.

To address the challenges of weak signals and poor system stability in Raman spectroscopy for trace gas detection, an enhanced spectroscopy technique based on a circular confocal cavity is proposed. This technique is centered on a circular multi-pass cell comprising multiple independent spherical mirrors, whose unique confocal configuration affords the system exceptional stability and alignment tolerance. A double-cycle optical path, realized through an integrated retro-reflector, doubles the effective optical path length while simultaneously collecting both forward and backward scattered signals, thereby maximizing collection efficiency. Under ambient conditions, a limit of detection (LOD) of 19 ppm for carbon dioxide was achieved within a 20-s integration time. This apparatus paves the way for the development of portable, high-sensitivity Raman gas analyzers.

Refractive error is a global public health challenge, with astigmatism correction being one of the key issues. While spherocylindrical lenses compensate for static astigmatism, they fail to address optical axis shifts during eye movement. To address this problem, we propose a single vision lens design method with freeform surfaces based on differentiable ray tracing. Our method integrates the rotation model of the human eye into the optical design framework. Besides, it leverages the high design freedom of the freeform surface to realize effective correction of optical focus errors across different fields of view. To verify the effectiveness of the method, we develop spectacle lens designs to correct astigmatism in the human eye through systematic comparison of traditional spherocylindrical and aspheric lenses with various freeform designs, including deformed XY polynomials and both single- and double-Zernike surfaces. Results show that our method achieves superior off-axis aberration correction at equivalent optimization orders, demonstrating its technical advantage for vision correction.

In this study, we demonstrate a hardware-efficient post-equalization implementation for PAM8 signals on an FPGA platform by utilizing an additive power-of-two (APoT) quantization scheme. This approach reduces hardware resource consumption by over 70% compared to conventional methods while preserving critical performance metrics. In a 300-m W-band wireless communication experiment, the system reliably transmits 22.1184 Gbit/s PAM8 signals and satisfies the 2.4 × 10^-2 soft-decision forward error correction (SD-FEC) standard. Notably, under a host-assisted workflow, the APoT scheme achieves performance equivalent to 16-bit uniform quantization and exhibits superior stability than PoT quantization.

We propose a scheme for dynamically controlling optical torque on Mie-sized particles using a single linearly polarized plane wave, assisted by a fixed coherent optical environment constructed from multiple interfering plane waves and designed using a back-propagation-based inverse design algorithm. Our design accounts for all physical mechanisms that can induce optical torque, rather than relying solely on spin angular momentum. Such an approach ensures an accurate one-to-one mapping between the polarization of the control wave and the resulting torque orientation. The method introduces an additional degree of freedom for dynamic and programmable torque control using simple, physically realizable plane waves and offers a strategy for polarization-encoded optical torque control.

After six years as Editor-in-Chief, Miguel A. Alonso will conclude his term, and Carsten Rockstuhl will take over the role on January 1, 2026. Just as the leadership of Optics Letters is changing, so are the publishing landscape, the field of optics and photonics, and the way in which scientists pursue their research activity. These changes prompted us to reflect on the past and future of the Journal in a permanently evolving environment.

We studied interference dislocations (forks) adjacent to an emission spot in an interference pattern. We observed the adjacent interference dislocations in emission of excitons in a monolayer transition metal dichalcogenide and in emission of spatially indirect excitons, also known as interlayer excitons, in a van der Waals heterostructure. Our simulations show that the adjacent interference dislocations appear due to the moiré effect in combined interference patterns produced by constituent parts of the emission spot. In contrast to interference dislocations in coherent states, such as interference dislocations due to quantized vortices in condensates, the appearance of adjacent interference dislocations does not require coherence between the parts of the emission spot, indicating that interference dislocations can be observed in a classical system. We show that the interference dislocations in classical systems can appear in interference images for various spatially modulated emission patterns.