用超短脉冲激光制造和测试极化激元材料

Strong Exciton-Photon Coupling in Large Area MoSe$_2$ and WSe$_2$ Heterostructures Fabricated from Two-Dimensional Materials Grown by Chemical Vapor Deposition

Two-dimensional semiconducting transition metal dichalcogenides embedded in optical microcavities in the strong exciton-photon coupling regime may lead to promising applications in spin and valley addressable polaritonic logic gates and circuits. One significant obstacle for their realization is the inherent lack of scalability associated with the mechanical exfoliation commonly used for fabrication of two-dimensional materials and their heterostructures. Chemical vapor deposition offers an alternative scalable fabrication method for both monolayer semiconductors and other two-dimensional mate…

单层半导体中非线性光子晶体极化激元的静电调控

Electrostatic control of nonlinear photonic-crystal polaritons in a monolayer semiconductor

本研究针对二维半导体-光子晶体平板集成结构中极化激元的可调性与非线性需求，通过静电门控嵌入MoSe₂的平面光子晶体平板，实现了可调的强极化激元非线性，发现两种不同非线性响应的共振可支持超短脉冲光开关，为有源极化激元器件的芯片级集成提供了新方向。

Topological Insulators: An in-depth Review of their Use in Modelocked Fiber Lasers

Topological Insulators (TIs) exhibit exciting optical properties, which opens up a new pathway to generate ultrashort pulses from fiber lasers. Layered TIs display distinct saturable absorption property due to excited state absorption, as compared to their bulk structures. Moreover, the electronic structures of the films of TIs depend on the thickness of the films due to the quantum confinement of the electrons. By virtue of this, the nanoparticles of TIs play a key role in all-fiber modelocked laser. By tweaking the crystal structures of TIs, it is possible to generate ultrashort pulses acros…

Laser-Induced Spatially-Selective Tailoring of High-Index Dielectric Metasurfaces

Optically resonant high-index dielectric metasurfaces featuring Mie-type electric and magnetic resonances are usually fabricated by means of planar technologies, which limit the degrees of freedom in tunability and scalability of the fabricated systems. Therefore, we propose a complimentary post-processing technique based on ultrashort ($\leq$ 10 ps) laser pulses. The process involves thermal effects: crystallization and reshaping, while the heat is localized by a high-precision positioning of the focused laser beam. Moreover, for the first time, the resonant behavior of dielectric metasurface…

Spatiotemporal control of surface plasmon polariton wave packets with nanocavities

Modulation of the optical index by means of atomic and material resonances provides a basis for controlling light propagation in natural and artificially fabricated materials. In addition, recent advances in the tuning of spatiotemporal couplings of ultrashort laser pulses have enabled almost arbitrary control over the group velocity of light. Here, using femtosecond time-resolved microscopy and numerical calculations, we investigate the spatiotemporal dynamics of a surface plasmon polariton wave packet (SPP WP) that interacts with a plasmonic nanocavity. The nanocavity consists of metal-insul…

Single-step fabrication of surface waveguides in fused silica with few-cycle laser pulses

Direct laser writing of surface waveguides with ultrashort pulses is a crucial achievement towards all-laser manufacturing of photonic integrated circuits sensitive to their environment. In this Letter, few-cycle laser pulses (with a sub-10 fs duration) are used to produce subsurface waveguides in a non-doped, non-coated fused silica substrate. The fabrication technique relies on laser-induced microdensification below the threshold for nanopore formation. The optical losses of the fabricated waveguides are governed by the optical properties of the superstrate. We have measured losses ranging f…

Fabrication of photonic nanostructures from hexagonal boron nitride

Growing interest in devices based on layered van der Waals (vdW) materials is motivating the development of new nanofabrication methods. Hexagonal boron nitride (hBN) is one of the most promising materials for studies of quantum photonics and polaritonics. Here, we report in detail on a promising nanofabrication processes used to fabricate several hBN photonic devices using a hybrid electron beam induced etching (EBIE) and reactive ion etching (RIE) technique. We highlight the shortcomings and benefits of RIE and EBIE and demonstrate the utility of the hybrid approach for the fabrication of su…

Bidirectional Soliton Rain Dynamics Induced by Casimir-Like Interactions in a Graphene Mode-Locked Fiber Laser

We study experimentally and theoretically the interactions among ultrashort optical pulses in the soliton rain multiple-pulse dynamics of a fiber laser. The laser is mode-locked by a graphene saturable absorber fabricated using the mechanical transfer technique. Dissipative optical solitons aggregate into pulse bunches that exhibit complex behavior, which includes acceleration and bi-directional motion in the moving reference frame. The drift speed and direction depend on the bunch size and relative location in the cavity, punctuated by abrupt changes under bunch collisions. We model the main …

All fiber ultrafast laser generating gigahertz pulse based on a hybrid plasmonic microfiber resonator

Ultrafast lasers generating high repetition rate ultrashort pulses through various mode-locking methods can benefit many important applications including communication, materials processing, astronomical observation, etc. For decades, mode-locking based on dissipative four-wave-mixing (DFWM) has been fundamental in producing pulses with repetition rates on the order of gigahertz (GHz), where multiwavelength comb filters and long nonlinear components are elemental. Recently, this method has been improved using filter-driven DFWM, which exploits both the filtering and nonlinear features of silic…

CrSBr光子晶体板中自杂化激子极子的磁性切换

Magnetic switching of self-hybridized exciton-polaritons in CrSBr photonic crystal slabs

研究CrSBr光子晶体板中自杂化激子极子的磁性调控，揭示极子群速度方向可逆转变，为磁控极子传输提供新平台。

超快laser刻写体相位光栅的性能

Performance of volume phase gratings manufactured using ultrafast laser inscription

超快激光刻蚀（ULI）是一种快速成熟的技术，其使用聚焦的超短激光脉冲在三维（3D）中局部改变电介质材料的折射率。近年来，超宽带已被应用于集成光束合成器、三维集成波导扇出器和多模-单模转换器（光子灯）等天文光子器件的制作。在这里，我们概述了我们的工作应用ULI的熔融石英和镓镧硫化物（GLS）玻璃的体相位光栅（VPG）的制造。我们制作的VPG具有333线/mm的空间频率。发现最佳熔融石英光栅在633 nm处表现出40%的一级衍射效率，但表现出约40%的积分散射光。最佳GLS光栅在633 nm处的一级衍射效率为71%，积分散射光小于5%。对于未来的天文学应用来说，重要的是，这两个光栅都能在冷却到20 K时幸存下来。本文总结了光栅设计和ULI制造工艺，并提供了详细的衍射效率性能和闪耀曲线的VPG。与传统的制造技术相比，ULI可以用于在几乎任何介电材料中制造VPG，包括中红外透射材料，例如这里使用的GLS玻璃。此外，ULI潜在地提供了产生复杂凹槽图案或闪耀光栅的自由度。由于这些原因，我们相信ULI为未来天文学相关应用的新型VPG开发开辟了道路。