Enhanced third harmonic generation from the epsilon-near-zero modes of ultrathin films

Epsilon-Near-Zero (ENZ) 模式对超薄膜间 Casimir 相互作用的影响

The Effect of Epsilon-Near-Zero (ENZ) Modes on the Casimir Interaction between Ultrathin Films

首次从实频率力分布角度研究超薄膜间 Casimir 相互作用，发现 ENZ 模式产生显著排斥贡献且与间距无关，揭示了其在纳米机械系统中的工程化潜力。

Plasmonic Light Trapping in an Ultrathin Photovoltaic Layer with Film-Coupled Metamaterial Structures

A film-coupled metamaterial structure is numerically investigated for enhancing the light absorption in an ultrathin photovoltaic layer of crystalline gallium arsenide (GaAs). The top subwavelength concave grating and the bottom metallic film could not only effectively trap light with the help of wave interference and magnetic resonance effects excited above the bandgap, but also practically serve as electrical contacts for photon-generated charge collection. The energy absorbed by the active layer is greatly enhanced in the film-coupled metamaterial structure, resulting in significant enhance…

Nearly-zero transmission through periodically modulated ultrathin metal films

Transmission of light through an optically ultrathin metal film with a thickness comparable to its skin depth is significant. We demonstrate experimentally nearly-zero transmission of light through a film periodically modulated by a one-dimensional array of subwavelength slits. The suppressed optical transmission is due to the excitation of surface plasmon polaritons and the zero-transmission phenomenon is strongly dependent on the polarization of the incident wave.

调控超薄铋膜在临界点附近的形貌以实现厚度优化的光学谐振腔

Tailoring the morphology of ultrathin bismuth films around percolation for thickness-optimized optical cavities

通过调控超薄铋膜在临界点附近的形貌，实现更紧凑的光学谐振腔设计，提升调谐范围和光学响应效率。

Magneto-optical properties of La2/3Sr1/3MnO3 ultrathin films

Pulse laser deposited La2/3Sr1/3MnO3 ultrathin films on SrTiO3 substrates were characterized by polar and longitudinal Kerr magneto-optical spectroscopy. An agreement between experimental and theoretical spectra was achieved for a 10.7 nm thick film, while a distinction in the Kerr effect amplitudes was obtained for a 5 nm thick film. This points to the slight suppression of ferromagnetism by interface effects. Nevertheless, the room temperature ferromagnetism of the 5 nm thick film was clearly demonstrated. All the studied films exhibit magneto-optical properties similar to single crystals an…

含硅层多层堆叠中超薄 a-Ge 薄膜的飞秒激光晶化

Femtosecond Laser Crystallization of Ultrathin a-Ge Films in Multilayer Stacks with Silicon Layers

本文用 1500 nm、70 fs 激光研究含硅多层堆叠中 3.5 nm a-Ge 薄膜的选择性晶化，发现其抑制应力诱导爆发式晶化而经由热熔化进行。

Spatiotemporally Separable Biphoton State Generated by Spontaneous Four Wave Mixing in Ultrathin Nonlinear Films

We theoretically investigated the biphoton state generated by spontaneous four wave mixing (SpFWM) in ultrathin nonlinear films. The expression of the biphoton state is obtained by perturbation method, in which the longitudinal phase mismatch term is eliminated due to the ultra-small nonlinear interactive length. As a result of the relaxation of the longitudinal phase match condition, frequency bandwidth of the biphoton state could be very large. The correlation function of the biphoton state is analyzed, showing that the space and time in the biphoton correlation of this state are factorable.…

Broadband perfect absorption of ultrathin conductive films with coherent illumination:Superabsorption of microwave radiation

Absorption of microwave by metallic conductors is exclusively inefficient, though being natively broadband, due to the huge impedance mismatch between metal and free space. Reducing the thickness to ultrathin conductive film may improve the absorbing efficiency, but is still bounded by a maximal 50% limit induced by the field continuity. Here, we show that broadband perfect (100%) absorption of microwave can be realized on a single layer of ultrathin conductive film when it is illuminated coherently by two oppositely incident beams. Such an effect of breaking the 50% limit maintains the intrin…

Film flip and transfer process to enhance light harvesting in ultrathin absorber films on specular back-reflectors

Optical interference is used to enhance light-matter interaction and harvest broadband light in ultrathin semiconductor absorber films on specular back-reflectors. However, the high-temperature processing in oxygen atmosphere required for oxide absorbers often degrades metallic back-reflectors and their specular reflectance. In order to overcome this problem, we present a newly developed film flip and transfer process that allows for high-temperature processing without degradation of the metallic back-reflector and without the need of passivation interlayers. The film flip and transfer process…

Giant Terahertz Polarization Rotation in Ultrathin Films of Aligned Carbon Nanotubes

For facile manipulation of polarization states of light for applications in communications, imaging, and information processing, an efficient mechanism is desired for rotating light polarization with a minimum interaction length. Here, we report giant polarization rotations for terahertz (THz) electromagnetic waves in ultrathin (~45 nm), high-density films of aligned carbon nanotubes. We observed polarization rotations of up to ~20° and ~110° for transmitted and reflected THz pulses, respectively. The amount of polarization rotation was a sensitive function of the angle between the incident TH…

超薄磁化 epsilon-near-zero 半导体中的非互易热辐射

Nonreciprocal thermal radiation in ultrathin magnetized epsilon-near-zero semiconductors

首次实验验证超薄磁化InAs半导体在ENZ频率下打破基尔霍夫热辐射定律，实现大于0.6的吸收与发射差异，并灵活调控单频、双频及宽带非互易热辐射，为革新下一代非互易能量器件奠定基础。

Implementing strong interference in ultrathin film top absorbers for tandem solar cells

Strong interference in ultrathin film semiconductor absorbers on metallic back reflectors has been shown to enhance the light harvesting efficiency of solar cell materials. However, metallic back reflectors are not suitable for tandem cell configurations because photons cannot be transmitted through the device. Here, we introduce a method to implement strong interference in ultrathin film top absorbers in a tandem cell configuration through use of distributed Bragg reflectors (DBRs). We showcase this by designing and fabricating a photoelectrochemical-photovoltaic (PEC-PV) stacked tandem cell …

Near-infrared single-photons from aligned molecules in ultrathin crystalline films at room temperature

We investigate the optical properties of Dibenzoterrylene (DBT) molecules in a spin-coated crystalline film of anthracence. By performing single molecule studies, we show that the dipole moments of the DBT molecules are oriented parallel to the plane of the film. Despite a film thickness of only 20 nm, we observe an exceptional photostability at room temperature and photon count rates around one million per second from a single molecule. These properties together with an emission wavelength around 800 nm make this system attractive for applications in nanophotonics and quantum optics.

Ultrathin and ultrasmooth gold films on monolayer MoS2

Sub-10 nm continuous metal films are promising candidates for flexible and transparent nanophotonics and optoelectronics applications. In this Letter, we demonstrate that monolayer MoS2 is a perspective adhesion layer for the deposition of continuous conductive gold films with a thickness of only 3-4 nm. Optical properties of continuous ultrathin gold films deposited on two-dimensional MoS2 grown by chemical vapor deposition are investigated by spectroscopic ellipsometry over a wide wavelength range (300-3300 nm). Results show that optical losses in ultrathin films increase with decreasing thi…