Self-Organization, Coherence and Turbulence in Laser Optics

In the last decades, rapid progress in modern nonlinear science was marked by the development of the concept of dissipative soliton (DS). This concept is highly useful in many different fields of science ranging from field theory, optics, and condensed matter physics to biology, medicine, and even sociology. This chapter aims to present a DS appearance from random fluctuations, development, and growth, the formation of the nontrivial internal structure of mature DS and its breakup, in other words, a full life cycle of DS as a self-organized object. Our extensive numerical simulations of the generalized cubic-quintic nonlinear Ginzburg-Landau equation, which models, in particular, dynamics of mode-locked fiber lasers, demonstrate a close analogy between the properties of DS and the general properties of turbulent and chaotic systems. In particular, we show a disintegration of DS into a noncoherent (or partially coherent) multisoliton complex. Thus, a DS can be interpreted as a complex of nonlinearly coupled coherent “internal modes” that allows developing the kinetic and thermodynamic theory of the nonequilibrious dissipative phenomena. Also, we demonstrate an improvement of DS integrity and, as a result, its disintegration suppression due to noninstantaneous nonlinearity caused by the stimulated Raman scattering. This effect leads to an appearance of a new coherent structure, namely, a dissipative Raman soliton

Dissipative Soliton Resonance: Adiabatic Theory and Thermodynamics

We present the adiabatic theory of dissipative solitons (DS) of complex cubic-quintic nonlinear Ginzburg-Landau equation (CQGLE). Solutions in the closed analytical form in the spectral domain have the shape of Rayleigh-Jeans distribution for a purely real quintic nonlinearity. The DS parametric space forms a two-dimensional (or three-dimensional for the complex quintic nonlinearity) master diagram connecting the DS energy and a universal parameter formed by the ratio of four real and imaginary coefficients for dissipative and non-dissipative terms in CQGLE. The concept of dissipative soliton resonance (DSR) is formulated in terms of the master diagram, and the main signatures of transition to DSR are demonstrated and experimentally verified. We show a close analogy between DS and incoherent (semicoherent) solitons with an ensemble of quasi-particles confined by a collective potential. It allows applying the thermodynamical approach to DS and deriving the conditions for the DS energy scalability.Comment: 31 pages, 15 figure

A route to high peak power and energy scaling in the mid-IR chirped-pulse oscillator-amplifier laser systems

The paper introduces a new route towards the ultrafast high laser peak power and energy scaling in a hybrid mid-IR chirped pulse oscillator-amplifier (CPO-CPA) system, without sacrificing neither the pulse duration nor energy. The method is based on using a CPO as a seed source allowing the beneficial implementation of a dissipative soliton (DS) energy scaling approach, coupled with a universal CPA technique. The key is avoiding a destructive nonlinearity in the final stages of an amplifier and compressor elements by using a chirped high-fidelity pulse from CPO. Our main intention is to realize this approach in a Cr2+:ZnS-based CPO as a source of energy-scalable DSs with well-controllable phase characteristics for a single-pass Cr2+:ZnS amplifier. A qualitative comparison of experimental and theoretical results provides a road map for the development and energy scaling of the hybrid CPO-CPA laser systems, without compromising pulse duration. The suggested technique opens up a route towards extremely intense ultra-short pulses and frequency combs from the multi-pass CPO-CPA laser systems that are particularly interesting for real-life applications in the mid-IR spectral range from 1 to 20 um.Comment: 16 pages, 14 figure

Supercontinuum generation in mid-IR using chalcogenide and germanate nonlinear fiber

We demonstrate mid-infrared (mid-IR) supercontinuum generation with bandwidth from 2 to 2.8 μm at 20 dB below the peak in nonlinear step-index chalcogenide fiber using femtosecond mid-IR pulses directly from the oscillator. We compare the results with a supercontinuum generated in a silica-based high germanium content fiber. Supercontinuum generation occurs at 90 mW of launched average pump power that is equal to the 0.9 nJ pulse energy. The distinctive feature of the obtained supercontinuum is its stability and coherence due to the deterministic supercontinuum generation by the femtosecond pump pulses

The Edinburgh human metabolic network reconstruction and its functional analysis

A better understanding of human metabolism and its relationship with diseases is an important task in human systems biology studies. In this paper, we present a high-quality human metabolic network manually reconstructed by integrating genome annotation information from different databases and metabolic reaction information from literature. The network contains nearly 3000 metabolic reactions, which were reorganized into about 70 human-specific metabolic pathways according to their functional relationships. By analysis of the functional connectivity of the metabolites in the network, the bow-tie structure, which was found previously by structure analysis, is reconfirmed. Furthermore, the distribution of the disease related genes in the network suggests that the IN (substrates) subset of the bow-tie structure has more flexibility than other parts

Efficient half-harmonic generation of three-optical-cycle mid-IR frequency comb around 4 µm using OP-GaP

We report a broadband mid-infrared frequency comb with three-optical-cycle pulse duration centered around 4.2 µm, via half-harmonic generation using orientation-patterned GaP (OP-GaP) with ~43% conversion efficiency. We experimentally compare performance of GaP with GaAs and lithium niobate as the nonlinear element, and show how properties of GaP at this wavelength lead to generation of the shortest pulses and the highest conversion efficiency. These results shed new light on half-harmonic generation of frequency combs, and pave the way for generation of short-pulse intrinsically-locked frequency combs at longer wavelengths in the mid-infrared with high conversion efficiencies

Quadratic Soliton Frequency Comb at 4 µm from an OP-GaP-based Optical Parametric Oscillator

We report generation of quadratic solitons, i.e. temporal simultons, in an OP-GaP based halfharmonic optical parametric oscillator. We achieve 4-µm pulses with sech² spectrum of 790nm FWHM bandwidth, 197% slope efficiency, and 38% conversion efficiency

Principles, advances and applications of ultrafast mid-infrared lasers

The talk reviews principles and advances in generation and applications of ultrashort pulses and frequency combs directly from the solid-state oscillator based on Cr2+ZnSe laser, and highlights radical efficiency and sensitivity increase when applied to high-resolution molecular spectroscopy

Femtosecond Cr2+-Based Lasers

We review a novel class of femtosecond Cr2+-doped ZnSe and ZnS lasers, which operates in a very important for applications wavelength range between 2 and 3.5 μm and which generates ultrashort optical pulses that are only five optical cycles in duration. Room-temperature Cr2+-lasers provide tens of Watts average power, >70% slope efficiency, ultrabroad tunability (~1400 nm between 2 and 3.4 μm) in the continuous wave regime and GW-level peak powers in the amplified femtosecond regime. Different mode-locking techniques from Kerr-lens to graphene saturable absorbers have been demonstrated, and dispersion compensation methods from bulk materials to chirped mirrors allowed the realization of self-starting few-optical cycle oscillators and the demonstration of a number of applications in spectroscopy and nonlinear optics. The Watt level few-optical cycle Cr:ZnS oscillator1 operating at 2.4 μm is distinguished by extremely short pulse duration of only 41 fs, hundreds of kilowatt peak powers, and tens of nanojoule pulse energies. Using the direct diode-pumping or fiber laser pump sources such a laser can be made reliable and compact, which paves the way to industrial realisation and applications in environmental analysis, oil and gas sensing, hazardous gas detection, breath analysis, fine material processing of semiconductors, composite materials, and glasses.The Austrian Science Fund ProjectThe EU-FET GRAPHENICSThe Norwe-gian Research Council ProjectsThe Nano 2021 Projec