Session Index

The impact of photons or energetic particles, such as electrons, introduces non-
equilibrium conditions in which many-body interactions can affect and determine the subse-
quent energy exchange pathways. These processes play an important role in surface-science
fragmentation and biological systems. In this study, we use real-time time-dependent density
functional theory (RT-TDDFT) to examine the autoionization process in water dimer, in which
initial inner shell ionization of a water monomer initializes an Intermolecular Coulomb Decay
(ICD) process that can further ionize the other water molecule leading to fragmentation of the
molecular species

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In this paper, regular pulses generated by the semiconductor lasers under optoelectronic feedback with ultrashort delay are analyzed and investigated. The study reveals a positive correlation between optoelectronic feedback strength and peak power. The higher the optoelectronic feedback strength, the higher the pick power and repetition frequency are observed. Detailed characteristics of the generated regular pulses are investigated, and the relations of each controllable parameter are also studied and compared.

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Dissipative soliton resonance in a unique mode-locking regime, which allows generating pulses with μJ level energies directly from the laser resonator. We present the first demonstration of using cross-phase modulation to synchronize the repetition rate of mode-locked fiber lasers working in the dissipative soliton resonance regime. High-energy synchronized pulses from lasers working at 1.06 μm and 1.55 μm are used to generate mode-locked pulses in the mid-infrared wavelength region via the difference frequency generation nonlinear effect. Parameters of the generated mid-IR radiation and the stability of the locking technique will be experimentally verified and discussed.

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This paper aims to investigate the influence of different C-ring sizes for N-metal electrodes on the
electrical properties and high-frequency characteristics of vertical-cavity surface-emitting lasers. Various C-ring
sizes were designed and measured under aperture sizes of 6 μm. The measurements include photoelectric
characteristic measurements, high-frequency response, and eye diagram analysis. The increase in the C-ring size
could lead to higher optical output power. However, for high-frequency communication, the parasitic
capacitance would be generated due to the increase in the N-metal area. Thus, the noise oscillation could lead to
a decrease in the high-frequency bandwidth.

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The laser-driven betatron source has matured to be one of the X-ray sources suitable for application in many research areas, its relatively compact footprint and permitting variable experimental geometries make it a possible alternative to large synchrotron radiation facilities. Our experiment used NCU 100TW laser system to generate ionization injection and utilize varying tilt angles of a sharp density transition to enhance X-ray production. The current results show that rotating tilt angles enhance the X-ray output signal by two times.

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This work presents the tunable generation of vortex, vector, and flat-top beams in a few-mode fiber with a mechanical long-period fiber grating. By the variation of applied force on the fiber grating, the core mode to higher-order mode excitation can be adjusted. The manipulation of the beam transformation is achieved through the polarization control of the fiber eigenmodes and mode coupling efficiency. By precisely tuning the intensity ratio between fundamental and doughnut modes, we arrive at the generation of propagation-invariant vector flat-top beams for more than 5 m.

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We present a surface modification of silicon nitride waveguide resonators using femtosecond laser annealing at 1035 nm. The surface morphologies were analyzed pre- and post-annealing using scanning phase-shifting interferometry and atomic force microscopy (AFM). Notably, at laser powers like 0.65W, surface roughness was enhanced to a mere 0.1nm. When applied to waveguide resonators, this annealing increased the quality (Q) factor by up to 1.33 times. Our study highlights the potential for efficient, cost-effective fabrication of low-loss integrated photonics through localized pulsed laser annealing.

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In this work, we constructed a range finder system using a homemade single longitudinal mode tunable laser and fiber coupled mach-zehnder interferometer. By measure the optical beat frequency between reference and return signals, the optical path difference can be calculated.

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Chirped mirrors present a valuable avenue for managing broadband dispersion in ultrafast optics, yet they are constrained by the extent of dispersion compensation. We've introduced a groundbreaking multiband design that redistributes group delay across various frequency bands, substantially boosting control and flexibility. Remarkably, the group delay dispersion of our mirror pair can be three to four times greater than that of existing ultrabroadband designs, with band separations exceeding an octave. Implemented in a multiphoton microscopy system, a chirped mirror pair successfully compressed pulses to their transform limits, 30fs and 23fs at 950nm and 1236nm wavelengths, respectively.

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We report the demonstration of an electro-optically (EO) switchable source based on a domain-engineered LiNbO3 operating in a closely lying, cross-polarized dual-line Nd:YLF laser. Simultaneous EO spectral switching and Q-switching at dual 1047- and 1053-nm cross-polarized lines, single 1047-nm line, single 1053-nm line, and their second-harmonic and sum-frequency generations have been realized with this novel laser system simply by voltage control.

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Modeling photoluminescence properties of a strong coupling unit consisting of molecules and a plasmonic nanocavity is challenging due to inclusion of vibration modes of molecules. In this report, photoluminescence excited by three different wavelengths is utilized. The alternation of fluorescence is observed, which may result from the variation of coupling strength during illumination. Furthermore, in addition to lower and upper polariton modes, the extra modes are observed. These results provide more insight into the molecule-cavity strong coupling

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