Light, science & applications最新文献

Ultrathin multifunctional metalenses are demonstrated to control the multiple degrees of freedom of a single-photon source in hexagonal boron nitride.

A highly efficient second-harmonic source is integrated into a silicon nitride microring resonator, unlocking the potential for advanced chip-scale devices such as miniaturized atomic clocks and fully integrated self-referenced microcombs.

Incorporating topological physics into the realm of quantum photonics holds the promise of developing quantum light emitters with inherent topological robustness and immunity to backscattering. Nonetheless, the deterministic interaction of quantum emitters with topologically nontrivial resonances remains largely unexplored. Here we present a single photon emitter that utilizes a single semiconductor quantum dot, deterministically coupled to a second-order topological corner state in a photonic crystal cavity. By investigating the Purcell enhancement of both single photon count and emission rate within this topological cavity, we achieve an experimental Purcell factor of F_p = 3.7. Furthermore, we demonstrate the on-demand emission of polarized single photons, with a second-order autocorrelation function g⁽²⁾(0) as low as 0.024 ± 0.103. Our approach facilitates the customization of light-matter interactions in topologically nontrivial environments, thereby offering promising applications in the field of quantum photonics.

Raising photoelectric conversion efficiency and enhancing heat management are two critical concerns for silicon-based solar cells. In this work, efficient Yb³⁺ infrared emissions from both quantum cutting and upconversion were demonstrated by adjusting Er³⁺ and Yb³⁺ concentrations, and thermo-manage-applicable temperature sensing based on the luminescence intensity ratio of two super-low thermal quenching levels was discovered in an Er³⁺/Yb³⁺ co-doped tungstate system. The quantum cutting mechanism was clearly decrypted as a two-step energy transfer process from Er³⁺ to Yb³⁺. The two-step energy transfer efficiencies, the radiative and nonradiative transition rates of all interested 4 f levels of Er³⁺ in NaY(WO₄)₂ were confirmed in the framework of Föster-Dexter theory, Judd-Ofelt theory, and energy gap law, and based on these obtained efficiencies and rates the quantum cutting efficiency was furthermore determined to be as high as 173% in NaY(WO₄)₂: 5 mol% Er³⁺/50 mol% Yb³⁺ sample. Strong and nearly pure infrared upconversion emission of Yb³⁺ under 1550 nm excitation was achieved in Er³⁺/Yb³⁺ co-doped NaY(WO₄)₂ by adjusting Yb³⁺ doping concentrations. The Yb³⁺ induced infrared upconversion emission enhancement was attributed to the efficient energy transfer ⁴I_11/2 (Er³⁺) + ²F_7/2 (Yb³⁺) → ⁴I_15/2 (Er³⁺) + ²F_5/2 (Yb³⁺) and large nonradiative relaxation rate of ⁴I_9/2. Analysis on the temperature sensing indicated that the NaY(WO₄)₂:Er³⁺/Yb³⁺ serves well the solar cells as thermos-managing material. Moreover, it was confirmed that the fluorescence thermal quenching of ²H_11/2/⁴S_3/2 was caused by the nonradiative relaxation of ⁴S_3/2. All the obtained results suggest that NaY(WO₄)₂:Er³⁺/Yb³⁺ is an excellent material for silicon-based solar cells to improve photoelectric conversion efficiency and thermal management.

Holographic 3D display is highly desirable for numerous applications ranging from medical treatments to military affairs. However, it is challenging to simultaneously achieve large viewing angle and high-fidelity color reconstruction due to the intractable constraints of existing technology. Here, we conceptually propose and experimentally demonstrate a simple and feasible pathway of using a well-designed color liquid crystal grating to overcome the inevitable chromatic aberration and enlarge the holographic viewing angle, thus enabling large-viewing-angle and color holographic 3D display. The use of color liquid crystal grating allows performing secondary diffraction modulation on red, green and blue reproduced images simultaneously and extending the viewing angle in the holographic 3D display system. In principle, a chromatic aberration-free hologram generation mechanism in combination with the color liquid crystal grating is proposed to pave the way for on such a superior holographic 3D display. The proposed system shows a color viewing angle of ~50.12°, which is about 7 times that of the traditional system with a single spatial light modulator. This work presents a paradigm for achieving desirable holographic 3D display, and is expected to provide a new way for the wide application of holographic display.

We demonstrate a novel flat-field, dual-optic imaging EUV-soft X-ray spectrometer and monochromator that attains an unprecedented throughput efficiency exceeding 60% by design, along with a superb spectral resolution of λ/Δλ > 200 accomplished without employing variable line spacing gratings. Exploiting the benefits of the conical diffraction geometry, the optical system is globally optimized in multidimensional parameter space to guarantee optimal imaging performance over a broad spectral range while maintaining circular and elliptical polarization states at the first, second, and third diffraction orders. Moreover, our analysis indicates minimal temporal dispersion, with pulse broadening confined within 80 fs tail-to-tail and an FWHM value of 29 fs, which enables ultrafast spectroscopic and pump-probe studies with femtosecond accuracy. Furthermore, the spectrometer can be effortlessly transformed into a monochromator spanning the EUV-soft X-ray spectral region using a single grating with an aberration-free spatial profile. Such capability allows coherent diffractive imaging applications to be conducted with highly monochromatic light in a broad spectral range and extended to the soft X-ray region with minimal photon loss, thus facilitating state-of-the-art imaging of intricate nano- and bio-systems, with a significantly enhanced spatiotemporal resolution, down to the nanometer-femtosecond level.

Exceptional points (EPs), singularities of non-Hermitian systems, often exhibit exotic behaviors by engineering the balance between the system gain and loss. Now, EPs have been demonstrated to enable unidirectional perfect absorption/reflection at the visible light spectrum.

Polarization-independent phase modulators based upon liquid crystals (LCs) with a simple device architecture have long been desired for a range of optical applications. Recently, researchers have demonstrated a novel fabrication procedure using cholesteric LCs as a primer for achieving low polarization dependence coupled with a large phase modulation depth.

Photoacoustic dual-comb spectroscopy (DCS), converting spectral information in the optical frequency domain to the audio frequency domain via multi-heterodyne beating, enables background-free spectral measurements with high resolution and broad bandwidth. However, the detection sensitivity remains limited due to the low power of individual comb lines and the lack of broadband acoustic resonators. Here, we develop cavity-enhanced photoacoustic DCS, which overcomes these limitations by using a high-finesse optical cavity for the power amplification of dual-frequency combs and a broadband acoustic resonator with a flat-top frequency response. We demonstrate high-resolution spectroscopic measurements of trace amounts of C₂H₂, NH₃ and CO in the entire telecommunications C-band. The method shows a minimum detection limit of 0.6 ppb C₂H₂ at the measurement time of 100 s, corresponding to the noise equivalent absorption coefficient of 7 × 10^-10cm^-1. The proposed cavity-enhanced photoacoustic DCS may open new avenues for ultrasensitive, high-resolution, and multi-species gas detection with widespread applications.

Miniaturizing spectrometers for compact and cost-effective mobile platforms is a major challenge in current spectroscopy research, where conventional spectrometers are impractical due to their bulky footprint. Existing miniaturized designs primarily rely on precalibrated response functions of nanophotonic structures to encode spectral information captured in a snapshot by detector arrays. Accurate spectrum reconstruction is achieved through computational techniques, but this requires precise component design, high-precision fabrication, and calibration. We propose an ultra-simplified computational spectrometer that employs a one-to-broadband diffraction decomposition strategy facilitated by a numerical regularized transform that depends only on the spectrum of the diffracted radiation. The key feature of our design is the use of a simple, arbitrarily shaped pinhole as the partial disperser, eliminating the need for complex encoding designs and full spectrum calibration. Our spectrometer achieves a reconstructed spectral peak location accuracy of better than 1 nm over a 200 nm bandwidth and excellent resolution for peaks separated by 3 nm in a bimodal spectrum, all within a compact footprint of under half an inch. Notably, our approach also reveals a breakthrough in broadband coherent diffractive imaging without requiring any prior knowledge of the broadband illumination spectrum, assumptions of non-dispersive specimens, or correction for detector quantum efficiency.