Dynamical instabilities of spectroscopic transitions in dense resonant media

Resonant Dampers for Parametric Instabilities in Gravitational Wave Detectors

Advanced gravitational wave interferometric detectors will operate at their design sensitivity with nearly 1MW of laser power stored in the arm cavities. Such large power may lead to the uncontrolled growth of acoustic modes in the test masses due to the transfer of optical energy to the mechanical modes of the arm cavity mirrors. These parametric instabilities have the potential of significantly compromising the detector performance and control. Here we present the design of "acoustic mode dampers" that use the piezoelectric effect to reduce the coupling of optical to mechanical energy. Exper…

利用光学腔谐振频率进行气体温度和浓度的光谱测量

Leveraging resonant frequencies of an optical cavity for spectroscopic measurement of gas temperature and concentration

本文提出利用光学腔谐振频率与分子谱线强度计算，实现高精度气体测温与浓度测量，不确定度达82 ppm，优于现有方法一个数量级。

Extreme Events in Resonant Radiation from Three-dimensional Light Bullets

We report measurements that show extreme events in the statistics of resonant radiation emitted from spatiotemporal light bullets. We trace the origin of these extreme events back to instabilities leading to steep gradients in the temporal profile of the intense light bullet that occur during the initial collapse dynamics. Numerical simulations reproduce the extreme valued statistics of the resonant radiation which are found to be intrinsically linked to the simultaneous occurrence of both temporal and spatial self-focusing dynamics. Small fluctuations in both the input energy and in the spati…

On the physical mechanism of three-wave instabilities -- resonance between positive- and negative-action modes

Three-wave instability is a fundamental process that has important applications in many branches of physics. It is widely accepted that the resonant condition $ω_{z}\approxω_{x}+ω_{y}$ for participating waves is the criteria for the onset of the instability. We show that this condition is neither sufficient nor necessary, instead, the exact criteria for the onset of the instability is that a positive-action mode resonates with a negative-action mode. This mechanism is imposed by the topology and geometry of the spectral space. Guided by this new theory, additional instability bands previously …

光子时变系统中的粒子-空穴不稳定性

Particle-hole instabilities in photonic time-varying systems

本文探讨了时变光子系统中由模式耦合与粒子-空穴对称性引发的正负频率振荡器共振相互作用，通过Drude-Lorentz模型证明色散与时空调制相互作用可导致参数不稳定性。

深紫外共振拉曼（DUVRR）光谱用于食品与农业样品的光谱评估和消毒

Deep ultraviolet resonant Raman (DUVRR) spectroscopy for spectroscopic evaluation and disinfection of food and agricultural samples

本文提出一种基于汞灯253.65 nm激发的便携式深紫外共振拉曼光谱系统，可分辨低于1000 cm⁻¹的拉曼峰，兼具高灵敏光谱评估与深紫外消毒功能，为农业和食品领域的精准检测与安全控制提供经济高效的工具。