- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Phase-Locked Programmable Femtosecond Pulse Bursts from a Regenerative Amplifier
摘要： We demonstrate phase-controlled pulse-burst amplification based on differential pathlength stabilization between the master oscillator and the amplifier cavities. This technique boosts the safe level of extractable burst energy and suppresses fluctuations in various burst-mode applications. OCIS codes: (190.4410) Nonlinear optics, parametric processes; (320.5540) Pulse shaping; (320.7160) Ultrafast technology Generation of amplified bursts of femtosecond pulses with tunable and extremely high, reaching into the THz regime, intra-burst frequencies is in high demand for various ultrafast laser applications such as burst-mode femtosecond ablation for materials processing [1], multipulse laser-induced breakdown spectrometry, several types of nonlinear and/or time-resolved spectroscopies and molecular quantum-information technologies [2]. In many cases, the desired inter-pulse spacing within a burst must range from 10 fs to several ps and is limited on the short side by the duration of an individual compressed fs pulse that dictates the minimum pulse separation without significant temporal overlap. In this contribution, we explore the opposite limit of the Vernier technique[3] and generate THz burst frequencies, which requires us to solve the problem of a nearly complete temporal overlap of the chirped pulse replicas enclosed in the RA and present a method for interferometrically stabilizing the relative pathlength difference between ?(cid:2)?(cid:4) and control of the carrier-envelope phases, CEP, of the pulses forming the (Fig.1a). We note, that the standard method practiced in femtosecond comb metrology and synchronously pumped OPOs are not appropriate in our case because the roundtrip time of one of the cavities must be flexibly varied to ensure continuous tuning of (cid:5)(cid:6)(cid:7)(cid:8)(cid:9)(cid:10). Therefore, our approach relies on direct ?(cid:2) stabilization with a readout of a spectral interference fringe produced by overlapping an outgoing MO pilot pulse that has completed a roundtrip through the RA cavity with the next incoming MO pulse at the full MO repetition rate, (cid:5)(cid:11)(cid:12)(cid:13) 76 MHz. Active RA cavity length stabilization is achieved via a PZT on one of the fold mirrors. The CEP scrambling, needed to suppress the formation of spectral modes, is achieved by programming the RF signal in the AOM which permits simultaneous and independent phase and amplitude shaping of each successive MO pulse. Fig.1b proves that in this way it is feasible to control the mode formation in the amplified burst spectrum without affecting the temporal envelope of the burst. Without the CEP scrambling, the energy performance of the RA would be very significantly restricted because the optical damage threshold is lowered as a result of inter-pulse interference[3]. Fig 1c shows the resulting interference recorded in the reference arm at 8 seconds the control electronics is switched off and the cavity is left floating.
关键词： Nonlinear optics,Pulse shaping,parametric processes,Ultrafast technology
更新于2025-09-16 10:30:52
-
[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Efficient 2-W Average Power 206 nm Deep-Ultraviolet Generation from 100-kHz Picosecond Pulses
摘要： We report on the generation of 2 W average power pulsed deep-ultraviolet radiation at 206 nm with few-picosecond pulse duration at a repetition rate of 100 kHz. The 206 nm radiation is derived in three steps by fifth harmonic generation from a 1030-nm, 1.6-ps Yb3+:YAG laser. The steps are second harmonic generation (SHG), fourth harmonic generation (FHG) and sum frequency generation (SFG), see Fig. 1 a). A nonlinear-optical beam flattening scheme together with group velocity matching by substantial pulse front tilts enable, to the author’s best knowledge, a new world record in average output power and conversion efficiency.
关键词： harmonic generation,beam flattening,deep-ultraviolet,picosecond pulses,nonlinear optics
更新于2025-09-16 10:30:52
-
White light continuum in negative hollow-core fiber filled with inert gases
摘要： As of the writing of this work, generation of white light continuum (WLC) in hollow-core photonic crystal ˉbers (HCPCF) ˉlled with gases is being thoroughly researched. These structures allow the possibility of adjusting light generation properties by changing the ˉll gas pressure. Kagom(cid:1)e hollow-core PCF and silica capillaries have been used to study the nonlinear e?ects in gases as they facilitate exploring these weak properties. In this paper, we numerically analyze the generation of WLC in a new type of hollow-core PCF, called negative curvature hollow-core ˉber (NCHCF), itself ˉlled with di?erent inert gases. We show that this type of ˉber is a better alternative to the Kagom(cid:1)e and capillary ˉbers because it exhibits low losses and the WLC spectrum generated presents a relatively °at wavelength span from around 400 nm to 2400 nm under certain circumstances.
关键词： inert gases,white light continuum,Nonlinear optics
更新于2025-09-16 10:30:52
-
Donor–acceptor type black phosphorus nanosheets covalently functionalized with a conjugated polymer for laser protection
摘要： Covalent functionalization of two-dimensional black phosphorus (BP) with conjugated polymers would be favorable to improve its environmental stability and solubility in organic solvents, and thereby to open a way to explore more applications of BP in the fields of optoelectronics, electronics and photonics. As a proof-of-concept application, soluble donor–acceptor type BP nanosheets covalently functionalized with poly[(1,4-diethynyl-2,5-bis(hexyloxy)benzene)-alt-benzo[c]thiadiazole] (hereafter called PDBT-BP) were synthesized through Sonogashira–Hagihara coupling polymerization, and embedded into an optically nonactive transparent poly(methylmethacrylate) (PMMA) matrix to produce the PMMA-based PDBT-BP film for nonlinear optics. In contrast to BP/PMMA, PDBT-BP/PMMA and PDBT/BP blends/PMMA films, the annealed PDBT-BP/PMMA film, which was heated at 150 °C under dry argon for 1 h, shows more excellent reverse saturable absorption (RSA) behavior, with a larger nonlinear absorption coefficient (βeff ) of 208.16 cm GW?1 and an imaginary third-order susceptibility (Im χ(3)) of 8.89 × 10?11 esu at a pulse energy of 400 μJ. The achieved optical limiting (OL) threshold is 4.44 J cm?2 (0.74 GW cm?2), smaller than that of the non-annealed PDBT-BP/PMMA film (5.64 J cm?2). The SA (saturable absorption) to RSA transition observed at a low incident laser intensity could be used to realize all-optical intensity-dependent logic gates in the near future.
关键词： Conjugated Polymer,Laser Protection,Polymer Chemistry,Black Phosphorus,Nonlinear Optics
更新于2025-09-16 10:30:52
-
Fundamentals and Applications of Nanophotonics || A dynamical, classical oscillator model for linear and nonlinear optics
摘要： In this chapter we will build and develop a self-consistent, classical oscillator model to describe linear and nonlinear optical interactions like refraction and frequency conversion in both centrosymmetric and noncentrosymmetric materials. In addition to being quite ubiquitous in all of physics, the classical oscillator model of matter is an enormously pedagogical tool that serves as a natural springboard to the description and understanding of quantum systems and leads to a rather detailed portrayal of all the dynamical factors that contribute to most linear and nonlinear optical phenomena. The method is endowed with causality as well as a natural degree of self-consistency that includes linear and nonlinear material dispersions, elements that are usually necessary to understand many of the subtleties of the interaction of light with matter. By way of examples, using this classical approach we will examine harmonic generation in bulk materials and in metal-based nanostructures. In centrosymmetric materials like metals (materials composed of molecules that lack a center of symmetry), second harmonic generation (SHG) arises mostly from nearly free, conduction electrons (nearly free because they are con?ned by the metal walls) and is due to a combination of spatial symmetry breaking (interfaces), the magnetic portion of the Lorentz force, and, to a lesser extent, the interaction of third harmonic (TH) and pump photons. By the same token, the third order nonlinearity (c(3)) gives rise to most of the TH signal, while to a small degree the interaction of pump and SH photons also produces cascaded, TH photons. The classical oscillator model will be pivotal in these systems as well, where a combination of free (Drude) and bound (Lorentz) electrons suf?ces to describe most linear and nonlinear optical phenomena.
关键词： Lorentz model,centrosymmetric materials,noncentrosymmetric materials,classical oscillator model,harmonic generation,linear and nonlinear optics,Drude model
更新于2025-09-16 10:30:52
-
[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Ultra-Broadband and Low Dispersion in Silicon-As <sub/>2</sub> S <sub/>3</sub> Slab/slot Waveguides for Supercontinuum Generation
摘要： A novel silicon- As2S3 slab/slot waveguide with an ultra-broadband (~5500nm) and low dispersion (from -7 and +19ps/nm/km) is proposed. As the slab introduced, the novel waveguide with three zero-dispersion wavelengths is obtained in the mid-infrared wavelength region from 3020 to 8500nm. The silicon- As2S3 slab/slot waveguide can be used to generate ultra-board supercontinuum ranging from 1.7 to 10.6μm. The proposed waveguide has great potential for ultra-broadband signal processing applications in near-infrared and mid-infrared region.
关键词： slab/slot waveguide,Nonlinear optics,Supercontinuum,dispersion
更新于2025-09-16 10:30:52
-
Wide-Span Multi-Wavelength High-Power Diode-Laser Pumping of Fiber Raman Laser
摘要： A multimode silica-core ?ber Raman laser was pumped directly by ?ve wavelength-combined multimode diode lasers. The pump wavelengths were spread over a bandwidth of ～700 cm?1, namely, at 976, 969, 950, 940, and 915 nm. This is larger than the Raman peak shift of 490 cm?1 . The output power reached 31.5 W with an overall slope ef?ciency of 42% at the wavelength of 1018 nm when pumped with the maximum launched power of 175 W. According to simulations, the ?ber was under-length and the output power could double in a longer ?ber. Our results suggest that pumping with spectrally combined diode lasers is a promising approach to high-power ?ber Raman lasers, even when the pump wavelengths are not optimized.
关键词： nonlinear optics,Raman lasers,Optical ?ber lasers
更新于2025-09-16 10:30:52
-
Interactions between M-typed dark solitons in nonlinear optics
摘要： Solitons are used in such field as nonlinear optics. In this manuscript, interactions between M-typed dark solitons are investigated analytically in the decreasing dispersion fiber. With symbolic computation, interactions between them are simulated via the analytic two-soliton solution. Relevant interaction characteristics of them are analyzed. Method of weakening soliton interaction is suggested.
关键词： Analytic solution,Dark solitons,Nonlinear optics,Decreasing dispersion fiber
更新于2025-09-16 10:30:52
-
Numerical Investigation on the Influence of Water Vapor Ionization on the Dynamic and Energy Deposition of Femtosecond Ultraviolet Laser Filamentation in Air
摘要： The e?ects of water vapor ionization on the nonlinear propagation of femtosecond laser pulses with a 248 nm wavelength are numerically investigated in this paper. It is found that ionization of H2O molecules plays a signi?cant role in air ionization, which seriously a?ects the dynamic and energy deposition of ?lamentation. The propagation of femtosecond pulses in air with di?erent humidity levels are compared. The total number of electrons and total deposited pulse energy increase with the humidity increases. However, they tend to be saturated in high humidity conditions. Results presented here are conducive to characterizing the long-range propagation of ?laments under atmospheric conditions.
关键词： multiphoton absorption,atmospheric propagation,self-focusing,water vapor,ultrafast nonlinear optics
更新于2025-09-16 10:30:52
-
Nonlinear optics at excited states of exciton polaritons in two-dimensional atomic crystals
摘要： Exciton polaritons (EP) are partial-light partial-matter quasiparticles in semiconductors demonstrating striking quantum phenomena such as Bose-Einstein condensation and single-photon nonlinearity. In these phenomena, the governing process is the EP relaxation into the ground states upon excitation, where various mechanisms are extensively investigated with thermodynamic limits. However, the relaxation process becomes drastically different and could significantly advance the understanding of EP dynamics for these quantum phenomena, when excited states of EP are involved. Here, for the first time, we observe nonlinear optical responses at the EP excited states in a monolayer tungsten disulphide (WS2) microcavity, including dark excited states and dynamically metastable upper polariton band. The nonlinear optics leads to unique emissions of ground states with prominent valley degree of freedom (DOF) via anomalous relaxation process, which is applicable to a wide range of semiconductors from monolayer transition metal dichalcogenides (TMDs) to emerging halide perovskites. This work promises possible approaches to challenging experiments such as valley polariton condensation. Moreover, it also constructs a valley-dependent solid state three-level system for terahertz photonics and stimulated Raman adiabatic passage.
关键词： excited states,exciton-polaritons,relaxation dynamics,Nonlinear optics,monolayer transition metal dichalcogenide
更新于2025-09-16 10:30:52