Light, science & applications最新文献

Vertically stacked all-organic active-matrix organic light-emitting diodes are promising candidates for high-quality skin-like displays due to their high aperture ratio, extreme mechanical flexibility, and low-temperature processing ability. However, these displays suffer from process interferences when interconnecting functional layers made of all-organic materials. To overcome this challenge, we present an innovative integration strategy called "discrete preparation-multilayer lamination" based on microelectronic processes. In this strategy, each functional layer was prepared separately on different substrates to avoid chemical and physical damage caused by process interferences. A single interconnect layer was introduced between each vertically stacked functional layer to ensure mechanical compatibility and interconnection. Compared to the previously reported layer-by-layer preparation method, the proposed method eliminates the need for tedious protection via barrier and pixel-defining layer processing steps. Additionally, based on active-matrix display, this strategy allows multiple pixels to collectively display a pattern of "1" with an aperture ratio of 83%. Moreover, the average mobility of full-photolithographic organic thin-film transistors was 1.04 cm² V^-1 s^-1, ensuring stable and uniform displays. This strategy forms the basis for the construction of vertically stacked active-matrix displays, which should facilitate the commercial development of skin-like displays in wearable electronics.

A body that violates Kirchhoff's law of thermal radiation exhibits an inequality in its spectral directional absorptivity and emissivity. Achieving such an inequality is of fundamental interest as well as a prerequisite for achieving thermodynamic limits in photonic energy conversion¹ and radiative cooling². Thus far, inequalities in the spectral directional emissivity and absorptivity have been limited to narrow spectral resonances³, or wavelengths well beyond the infrared regime⁴. Bridging the gap from basic demonstrations to practical applications requires control over a broad spectral range of the unequal spectral directional absorptivity and emissivity. In this work, we demonstrate broadband nonreciprocal thermal emissivity and absorptivity by measuring the thermal emissivity and absorptivity of gradient epsilon-near-zero InAs layers of subwavelength thicknesses (50 nm and 150 nm) with an external magnetic field. The effect occurs in a spectral range (12.5-16 μm) that overlaps with the infrared transparency window and is observed at moderate (1 T) magnetic fields.

Independent controls of various properties of electromagnetic (EM) waves are crucially required in a wide range of applications. Programmable metasurface is a promising candidate to provide an advanced platform for manipulating EM waves. Here, we propose an approach that can arbitrarily control the polarization direction and phases of reflected waves in linear and nonlinear ways using a stacked programmable metasurface. Further, we extend the space-time-coding theory to incorporate the dimension of polarization, which provides an extra degree of freedom for manipulating EM waves. As proof-of-principle application examples, we consider polarization rotation, phase manipulation, and beam steering at linear and nonlinear frequencies. For validation, we design, fabricate, and measure a metasurface sample. The experimental results show good agreement with theoretical predictions and simulations. The proposed approach has a wide range of applications in various areas, such as imaging, data storage, and wireless communication.

The emitter-cavity strong coupling manifests crucial significance for exploiting quantum technology, especially in the scale of individual emitters. However, due to the small light-matter interaction cross-section, the single emitter-cavity strong coupling has been limited by its harsh requirement on the quality factor of the cavity and the local density of optical states. Herein, we present a strategy termed waveguide-assisted energy quantum transfer (WEQT) to improve the single emitter-cavity coupling strength by extending the interaction cross-section. Multiple ancillary emitters are optically linked by a waveguide, providing an indirect coupling channel to transfer the energy quantum between target emitter and cavity. An enhancement factor of coupling strength $\tilde{g}/g>10$ can be easily achieved, which dramatically release the rigorous design of cavity. As an extension of concept, we further show that the ancillae can be used as controlling bits for a photon gate, opening up new degrees of freedom in quantum manipulation.

3-dB couplers, which are commonly used in photonic integrated circuits for on-chip information processing, precision measurement, and quantum computing, face challenges in achieving robust performance due to their limited 3-dB bandwidths and sensitivity to fabrication errors. To address this, we introduce topological physics to nanophotonics, developing a framework for topological 3-dB couplers. These couplers exhibit broad working wavelength range and robustness against fabrication dimensional errors. By leveraging valley-Hall topology and mirror symmetry, the photonic-crystal-slab couplers achieve ideal 3-dB splitting characterized by a wavelength-insensitive scattering matrix. Tolerance analysis confirms the superiority on broad bandwidth of 48 nm and robust splitting against dimensional errors of 20 nm. We further propose a topological interferometer for on-chip distance measurement, which also exhibits robustness against dimensional errors. This extension of topological principles to the fields of interferometers, may open up new possibilities for constructing robust wavelength division multiplexing, temperature-drift-insensitive sensing, and optical coherence tomography applications.

Quantum entanglement has emerged as a great resource for studying the interactions between molecules and radiation. We propose a new scheme of stimulated Raman scattering with entangled photons. A quantum ultrafast Raman spectroscopy is developed for condensed-phase molecules, to monitor the exciton populations and coherences. Analytic results are obtained, showing an entanglement-enabled time-frequency scale not attainable by classical light. The Raman signal presents an unprecedented selectivity of molecular correlation functions, as a result of the Hong-Ou-Mandel interference. Our work suggests a new paradigm of using an unconventional interferometer as part of spectroscopy, with the potential to unveil advanced information about complex materials.

A single-shot near-infrared probing method has been developed to characterize the formation and evolution of the pre-plasma dynamics over sub-picosecond timescales, which is essential for the societal applications of laser-accelerated ion technologies.

We present a novel time-of-flight resolved Bessel light bullet-enabled stimulated Raman scattering (B²-SRS) microscopy for deeper tissue 3D chemical imaging with high resolution without a need for mechanical z-scanning. To accomplish the tasks, we conceive a unique method to enable optical sectioning by generating the counter-propagating pump and Stokes Bessel light bullets in the sample, in which the group velocities of the Bessel light bullets are made ultraslow (e.g., v_g ≈ 0.1c) and tunable by introducing programmable angular dispersions with a spatial light modulator. We theoretically analyze the working principle of the collinear multicolor Bessel light bullet generations and velocity controls with the relative time-of-flight resolved detection for SRS 3D deep tissue imaging. We have also built the B²-SRS imaging system and present the first demonstration of B²-SRS microscopy with Bessel light bullets for 3D chemical imaging in a variety of samples (e.g., polymer bead phantoms, biological samples such as spring onion tissue and porcine brain) with high resolution. The B²-SRS technique provides a > 2-fold improvement in imaging depth in porcine brain tissue compared to conventional SRS microscopy. The method of optical sectioning in tissue using counter-propagating ultraslow Bessel light bullets developed in B²-SRS is generic and easy to perform and can be readily extended to other nonlinear optical imaging modalities to advance 3D microscopic imaging in biological and biomedical systems and beyond.