理学最新文献

A widely tested approach to overcoming the diffraction limit in microscopy without disturbing the sample relies on substituting widefield sample illumination with a structured light beam. This gives rise to confocal, image scanning, and structured illumination microscopy methods. On the other hand, as shown recently by Tsang and others, subdiffractional resolution at the detection end of the microscope can be achieved by replacing the intensity measurement in the image plane with spatial mode demultiplexing. In this work, we study the combined action of Tsang’s method with image scanning. We experimentally demonstrate superior lateral resolution and enhanced image quality compared to either method alone. This result paves the way for integrating spatial demultiplexing into existing microscopes, contributing to further pushing the boundaries of optical resolution.

Scintillators have been widely used in X-ray imaging due to their ability to convert high-energy radiation into visible light, making them essential for applications such as medical imaging and high-energy physics. Recent advances in the artificial structuring of scintillators offer new opportunities for improving the energy resolution of scintillator-based X-ray detectors. Here, we present a three-bin energy-resolved X-ray imaging framework based on a three-layer multicolor scintillator used in conjunction with a physics-aware image postprocessing algorithm. The multicolor scintillator is able to preserve X-ray energy information through the combination of emission wavelength multiplexing and energy-dependent isolation of X-ray absorption in specific layers. The dominant emission color and the radius of the spot measured by the detector are used to infer the incident X-ray energy based on prior knowledge of the energy-dependent absorption profiles of the scintillator stack. Through ab initio Monte Carlo simulations, we show that our approach can achieve an energy reconstruction accuracy of 49.7%, which is only 2% below the maximum accuracy achievable with realistic scintillators. We apply our framework to medical phantom imaging simulations where we demonstrate that it can effectively differentiate iodine and gadolinium-based contrast agents from bone, muscle, and soft tissue.

Blue phosphorescent OLEDs (Ph-OLEDs) have long faced critical challenges in efficiency, stability and brightness, which are crucial for advanced display. Herein, we introduce two novel Ir(III) emitters featuring a 3,6-di(tert-butyl)-9H-carbazolyl (tBuCz) substituted tridentate carbene pincer ligand, significantly improving efficiency and stability. The tBuCz-m-CF3 and tBuCz-p-CF3 complexes are designed to enhance steric encumbrance and minimize exciton accumulation. These innovations lead to exceptional photoluminescence quantum yields (PLQY) of 98% and an impressive decay rate constant of 7.97 × 10⁵ s⁻¹ in doped thin films. The Ph-OLEDs emit blue light with a peak wavelength of 485 nm and CIE coordinates of (0.175, 0.446), exhibiting a peak external quantum efficiencies (EQE) of 31.62% and brightness up to 214,255 cd m⁻². Notably, they shown minimal efficiency roll-off, retaining an EQE of 27.76% at 10,000 cd m⁻², and 20.58% at 100,000 cd m⁻². These consistent performances across various brightness levels represent a significant milestone for blue Ph-OLED technology. The devices also exhibit impressive stability, with an operational lifetime (LT₅₀, the time taken for luminance to decrease by 50%) reaching 1237 h at 1000 cd m⁻², setting new benchmarks for blue Ph-OLEDs. To enhance the color purity, hyper-OLEDs were developed with a full width at half maximum (FWHM) of 20 nm and the CIEy of 0.233, achieving an EQE_m of 29.78% and LT₅₀ of 318 h at 1000 cd m⁻². We also fabricated the active-matrix (AM) blue Hyper-OLEDs with 400 pixels per inch to demonstrate their application in AM displays.

Achieving non-reciprocal optical behavior in integrated photonics with high efficiency has long been a challenge. Here, we demonstrate a non-reciprocal magneto-optic response by integrating multilayer 2D CuCrP₂S₆ (CCPS) onto silicon microring resonators (MRRs). Under an applied magnetic field, the CCPS intralayer ferromagnetic ordering, characterized by easy-plane magneto-crystalline anisotropy, induces asymmetrical modal responses in the clockwise (CW) and counterclockwise (CCW) light propagation directions. The proposed configuration achieves a low insertion loss ranging from 0.15 dB to 1.8 dB and a high isolation ratio of 28 dB at 1550 nm. Notably, it exhibits a significant resonance wavelength splitting of 0.4 nm between the counter propagation directions, supporting a 50 GHz optical bandwidth. Operating directly in the transverse electric (TE) mode, it aligns with the main polarization used in silicon photonics circuits, eliminating the need for additional polarization management. The device is ultra-compact, with a 2D flake interaction length ranging from 22 µm to 55 µm and a thickness between 39 nm and 62 nm. Its operation range covers the entire C-band with a bandwidth of up to 100 nm. These attributes make our hybrid CCPS/Si device ideal for advanced non-reciprocal optical applications in the short-wave infrared (SWIR) spectrum, crucial for enhancing the resilience of optical systems against back-reflections.

Orbital angular momentum (OAM) research has evolved from a theoretical concept to a tool with diverse applications. Early advancements distinguished OAM from spin angular momentum (SAM), leading to practical innovations such as optical tweezers and quantum entanglement. Compared with SAM, OAM can carry more information, which makes it invaluable for high-capacity data transmission and secure communications. Professor Miles Padgett, a leading scientist in the field of optical momentum, is well-known for his contributions, including the realization of an optical spanner for spinning micron-sized objects, the use of orbital angular momentum to increase the data capacity for communication systems, and the development of an angular form of the Einstein‒Podolky‒Rosen (EPR) quantum paradox. In an enlightening conversation with Light: Science & Applications, he highlighted the fundamental properties of the angular momentum of light, the invention of optical tweezers and optical spanners, and the demonstration of OAM states for extending the alphabet of optical communication using both classical and quantum light. In particular, he explained the various aspects of OAM distinguished from SAM. This interview further explored his collaboration with industry partners that bridges the gap between academic research and real-world applications by using his skill in light shaping in various areas, including his current role as the principal investigator for QuantIC and his group’s work on building novel endoscopes that are the size of the width of a human hair.

As an academic administrator, during his 5-year term as Vice-Principal for Research at the University of Glasgow (2014–2019), Professor Miles Padgett’s efforts led to an improvement in the quality of the University’s research publications from the lower quartile to the upper quartile in the Russell Group of the UKs leading universities. In this interview, he shared his approach to improve research culture to build up research collaboration, secure external funding for conducting cutting-edge research, and translate blue-sky research into real-world impact. In addition to his research success, Miles also serves many important roles for research societies and funding agencies. For example, as the Interim Executive Chair for EPSRC in 2023, his tenure successfully led to a nearly 50% increase in the number of funded Centres for Doctoral Training, corresponding to an additional intake of 1500 students. When asked about his motivation to serve on research committees, he expressed his ambition to shape the direction of science, advocating for areas of science with the potential to impact society. For young scientists, his advice is to understand that perseverance and adaptability are crucial for research career progress while remembering that luck also plays a role—sometime you just have to hang on in.

Nonlinear optical metasurfaces, which relax the phase-matching constraints of bulk nonlinear crystals and allow for precise engineering, are opening new possibilities in the field of quantum photonics. Recent advancements have experimentally demonstrated high-resolution 2D imaging using a 1D detector array by combining quantum ghost imaging and all-optical scanning with spatially entangled photon pairs generated from a nonlinear metasurface. These findings establish metasurfaces as a promising platform for quantum imaging, communications, and sensing applications.

Phase transitions induce significant changes in the electrical and photonic properties of materials. Ultra-sensitive photodetectors leveraging material phase transitions can be realized near the transition temperature. Photodetectors based on Ta₂NiSe₅, a room-temperature excitonic insulator phase transition material, exhibit exceptional performance from visible to terahertz frequencies. Specifically, in the terahertz range, the electronic bandwidth is 360 kHz, and the specific detectivity (D*) reaches 5.3 × 10¹¹ cm·Hz^1/2·W⁻¹. The van der Waals heterostructure of Ta₂NiSe₅/WS₂ further enhances performance.

A mid-infrared orbital angular momentum detector based on multilayer graphene has been successfully developed, overcoming the previous reliance on C_2V point group topological Weyl semimetals via the orbital photogalvanic effect. This CMOS-compatible two-dimensional material system is crucial for advancing the large-scale practical application of orbital angular momentum detectors.

Controlling the tissue temperature rise during retinal laser therapy is essential for predictable outcomes, especially at non-damaging settings. We demonstrate a method for determining the temperature rise in the retina using phase-sensitive optical coherence tomography (pOCT) in vivo. Measurements based on the thermally induced optical path length changes (ΔOPL) in the retina during a 10-ms laser pulse allow detection of the temperature rise with a precision less than 1 °C, which is sufficient for calibration of the laser power for patient-specific non-damaging therapy. We observed a significant difference in confinement of the retinal deformations between the normal and the degenerate retina: in wild-type rats, thermal deformations are localized between the retinal pigment epithelium (RPE) and the photoreceptors’ inner segments (IS), as opposed to a deep penetration of the deformations into the inner retinal layers in the degenerate retina. This implies the presence of a structural component within healthy photoreceptors that dampens the tissue expansion induced by the laser heating of the RPE and pigmented choroid. We hypothesize that the thin and soft cilium connecting the inner and outer segments (IS, OS) of photoreceptors may absorb the deformations of the OS and thereby preclude the tissue expansion further inward. Striking difference in the confinement of the retinal deformations induced by a laser pulse in healthy and degenerate retina may be used as a biomechanical diagnostic tool for the characterization of photoreceptors degeneration.

The generation of optical vortices in compact systems and across different spectral regions can open new horizons for their applications in end-user devices. Latest advances in the design and fabrication of optical metasurfaces made of a quadratically nonlinear material enable highly precise creation of vortices with different topological charges at the second-harmonic frequency, with the potential to obtain various other structured states of light.