Search results for "spontaneous emission"

Mechanisms of Spontaneous and Amplified Spontaneous Emission in CH3NH3PbI3 Perovskite Thin Films Integrated in an Optical Waveguide

2020

In this paper, the physical mechanisms responsible for optical gain in ${\mathrm{CH}}_{3}{\mathrm{NH}}_{3}{\mathrm{Pb}\mathrm{I}}_{3}$ (MAPI) polycrystalline thin films are investigated experimentally and theoretically. Waveguide structures composed by a MAPI film embedded in between PMMA and silica layers are used as an efficient geometry to confine emitted light in MAPI films and minimize the energy threshold for amplified spontaneous emission (ASE). We show that photogenerated exciton density at the ASE threshold is as low as $(2.4\ensuremath{-}12)\ifmmode\times\else\texttimes\fi{}{10}^{16}\phantom{\rule{0.1em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}3}$, which is below the Mott transition den…

Temperature dependence of Photoluminescence and Amplified Spontaneous Emission in thin films of quasi-2D BA3MA3Pb5Br16 perovskites

2021

ASE narrow‐band noise pulsing in erbium‐doped fiber amplifier and its effect on self‐phase modulation

2019

In this paper, we report a study of the features of polarized and unpolarized narrow-band amplified spontaneous emission (ASE) in a low-doped erbium fiber at 976-nm pumping. We demonstrate that ASE noise can be treated as a train of Gaussian-like pulses with random magnitudes, widths, and inter-pulse intervals. ASE noise can also provide a statistical analysis of these three parameters. We also present the data that reveal ASE noise’s role in optical spectrum broadening through self-phase modulation of light propagating in a communication fiber. In particular, the data show that the ASE noise derivative defines the broadening’s spectral shape.

Single-Exciton Amplified Spontaneous Emission in Thin Films of CsPbX3 (X = Br, I) Perovskite Nanocrystals

2019

CsPbX3 perovskite nanocrystals (PNCs) have emerged as an excellent material for stimulated emission purposes, with even more prospective applications than conventional colloidal quantum dots. However, a better understanding of the physical mechanisms responsible for amplified spontaneous emission (ASE) is required to achieve more ambitious targets (lasing under continuous wave optical or electrical excitation). Here, we establish the intrinsic mechanisms underlying ASE in PNCs of three different band gaps (CsPbBr3, CsPbBr1.5I1.5, and CsPbI3). Our characterization at cryogenic temperatures does not reveal any evidence of the biexciton mechanism in the formation of ASE. Instead, the measured …

Er-doped photonic crystal fibre characterization method based on McCumber theory

2009

Characterization and modeling of Er-doped fibres [1] allowed in the past years fruitful developments of amplifiers and lasers. Since in a conventional fibre monomodal propagation of light is achieved in a very short length (once energy of other modes has been radiated) the cutback technique has been successfully used to determine absorption cross sections at the pump and gain band wavelengths. Emission cross sections have been usually determined instead from the measurement of gain or amplified spontaneous emission (ASE) spectrum together with the use of theoretical models. In a photonic crystal fibre (PCF) the limited size of the air-holes lattice originates energy radiation from the highe…

Beneficial impact of wave-breaking for coherent continuum formation in normally dispersive nonlinear fibers

2008

International audience; We study the evolution of a pulse propagating in a normally dispersive fiber in the presence of Kerr nonlinearity. We review the temporal and spectral impact of optical wave-breaking in the development of a continuum. The impact of linear losses or gain is also investigated.

Stimulated emission and optical properties of pyranyliden fragment containing compounds in PVK matrix

2017

This work has been supported by National Research program “Multifunctional materials and composites, photonics and nanotechnology (IMIS2)”. Financial support provided by Scientific Research Project for Students and Young Researchers No. SJZ2015/12 realised at the Institute of Solid State Physics, University of Latvia is greatly acknowledged.

Amplified Spontaneous Emission in Thin Films of CsPbX3 Perovskite Nanocrystals

2019

During the last years, Metal Halide Perovskites (MHPs) have attracted special attention as an efficient conversion films for photovoltaics, or excellent gain media to construct optical sources. In spite of the fact that most of the works have been focussed on CH 3 NH 3 PbX 3 (X=Cl, Br, I) polycrystalline thin films, MHP can be also synthesized as colloidal nanocrystals. In particular, caesium lead halide perovskite CsPbX 3 nanocrystals (NCs) revealed extraordinary properties for optoelectronics. With a high quantum yield of emission (>90%) at room temperature and linewidths less than 100 meV, CsPbX 3 NCs have demonstrated favourable characteristics for active photonics. Indeed, thin films o…

Amplified spontaneous emission in thin films of quasi-2D BA3MA3Pb5Br16 lead halide perovskites

2021

Quasi-2D (two-dimensional) hybrid perovskites are emerging as a new class of materials with high photoluminescence yield and improved stability compared to their three-dimensional (3D) counterparts. Nevertheless, despite their outstanding emission properties, few studies have been reported on amplified spontaneous emission (ASE) and a thorough understanding of the photophysics of these layered materials is still lacking. In this work, we investigate the ASE properties of multilayered quasi-2D BA3MA3Pb5Br16 films through the dependence of the photoluminescence on temperature and provide a novel insight into the emission processes of quasi-2D lead bromide perovskites. We demonstrate that the …

Concentration dependence of amplified spontaneous emission in two oligo-(p-phenylenevinylene) derivatives

2005

Amplified spontaneous emission sASEd in optically pumped polystyrene sPSd films doped with two different oligo-sp-phenylenevinylened derivatives sOPVsd, with three s3-OPVd and five s5-OPVd monomer units is reported. It is observed that there is a maximum content of oligomer s25 wt. % for 3-OPV and 20 wt. % for 5-OPVd that can be introduced in the films, due to degradation sin 3-OPVd and ASE quenching sin 5-OPVd. Optimal concentrations swith minimum pump-intensity thresholds for the observation of ASEd of 15 wt. % and 9 wt. % are measured for the trimer and the pentamer, respectively. The concentration dependence of the ASE threshold is discussed in terms of the optical absorption spectra. G…