scholarly journals Amplified Spontaneous Emission and Optical Gain in Organic Single Crystal Quinquethiophene

Crystals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 609 ◽  
Author(s):  
Muhammad Zeb ◽  
Muhammad Tahir ◽  
Fida Muhammad ◽  
Suhana Mohd Said ◽  
Mohd Faizul Mohd Sabri ◽  
...  
Keyword(s):  
Single Crystal ◽  
Spontaneous Emission ◽  
Threshold Energy ◽  
Pump Energy ◽  
Optical Gain ◽  
Amplified Spontaneous Emission ◽  
Stimulated Emission ◽  
Excitation Wavelength ◽  
Optical Amplification ◽  
Organic Single Crystal

In this paper, we report optical characteristics of an organic single crystal oligomer 5,5⁗-diphenyl-2,2′:5′,2″:5″,2‴:5‴,2⁗-quinquethiophene (P5T). P5T crystal is a thiophene/phenylene co-oligomer that possesses better charge mobility as well as photoluminescence quantum efficiency (PLQE) as compared to other organic materials. Stimulated emission in P5T is investigated via amplified spontaneous emission (ASE) measurements within broad pump energies ranging from 35.26 to 163.34 µJ/cm2. An Nd-YAG femtosecond-tunable pulsed laser is used as a pump energy source for the ASE measurements of P5T crystals at an excitation wavelength of 445 nm. The ASE spectra exhibit optical amplification in P5T crystals at a 625 nm peak wavelength with a lower threshold energy density (Eth) ≈ 52.64 μJ/cm2. P5T also demonstrates higher optical gain with a value of 72 cm−1, that is calculated by using the variable stripe-length method. The value of PLQE is measured to be 68.24% for P5T. This study proposes potential applications of P5T single crystals in organic solid state lasers, photodetectors, and optical amplifiers.

scholarly journals Investigation of Threshold Carrier Densities in the Optically Pumped Amplified Spontaneous Emission of Formamidinium Lead Bromide Perovskite Using Different Excitation Wavelengths

Photonics ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 4
Author(s):  
Saif M. H. Qaid ◽  
Hamid M. Ghaithan ◽  
Khulod K. AlHarbi ◽  
Abrar F. Bin Ajaj ◽  
Bandar Ali Al-Asbahi ◽  
...  
Keyword(s):  
Energy Density ◽  
Spontaneous Emission ◽  
Threshold Energy ◽  
Amplified Spontaneous Emission ◽  
The Other ◽  
Excitation Wavelength ◽  
Optically Pumped ◽  
Threshold Energy Density ◽  
Other Hand ◽  
Lead Bromide

The high crystal quality of formamidium lead bromide perovskite (CH(NH2)2PbBr3 = FAPbBr3) was infiltrated in a mesoporous TiO2 network. Then, high-quality FAPbBr3 films were evaluated as active lasing media, and were irradiated with a picosecond pulsed laser to demonstrate amplified spontaneous emission (ASE), which is a better benchmark of its intrinsic suitability for gain applications. The behavior was investigated using two excitation wavelengths of 440 nm and 500 nm. Due to the wavelength-dependent absorbance spectrum and the presence of a surface adsorption layer that could be reduced using the shorter 440 nm wavelength, the ASE power dependence was strongly reliant on the excitation wavelength. The ASE state was achieved with a threshold energy density of ~200 µJ/cm2 under 440 nm excitation. Excitation at 500 nm, on the other hand, needed a higher threshold energy density of ~255 µJ/cm2. The ASE threshold carrier density, on the other hand, was expected to be ~4.5 × 1018 cm−3 for both excitations. A redshift of the ASE peak was detected as bandgap renormalization (BGR), and a BGR constant of ~5–7 × 10−9 eV cm was obtained.

scholarly journals Random lasing and amplified spontaneous emission from silk inverse opals: Optical gain enhancement via protein scatterers

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Muhammad Umar ◽  
Kyungtaek Min ◽  
Sookyoung Kim ◽  
Sunghwan Kim
Keyword(s):  
Spontaneous Emission ◽  
High Surface ◽  
Optical Gain ◽  
Amplified Spontaneous Emission ◽  
Biological Tissues ◽  
Light Sources ◽  
Inverse Opal ◽  
Random Lasing ◽  
Protein Film ◽  
Gain Enhancement

Abstract Gain amplification and coherent lasing lines through random lasing (RL) can be produced by a random distribution of scatterers in a gain medium. If these amplified light sources can be seamlessly integrated into biological systems, they can have useful bio-optical applications, such as highly accurate sensing and high-resolution imaging. In this paper, a fully biocompatible light source showing RL and amplified spontaneous emission (ASE) with a reduced threshold is reported. Random cavities were induced in a biocompatible silk protein film by incorporating an inverse opal with an inherent disorder and a biocompatible dye for optical gain into the film. By choosing the appropriate air-sphere diameters, clear RL spikes in the emission spectra that were clearly distinguished from those of the ASE were observed in the silk inverse opal (SIO) with optical gain. Additionally, the RL output exhibited spatial coherence; however, the ASE did not. The high surface-to-volume ratio and amplification of the SIO led to highly efficient chemosensing in the detection of hydrogen chloride vapor. Moreover, SIO could be miniaturized to be made suitable for injection into biological tissues and obtain RL signals. Our results, which open the way for the development of a new generation of miniaturized bio-lasers, may be considered as the first example of engineered RL with biocompatible materials.

scholarly journals Synthesis, optical properties, and amplified spontaneous emission of hybrid Ag–SiO2–CdTe nanocomposite

2017 ◽  
Vol 95 (10) ◽  
pp. 933-940
Author(s):  
A.M. Saad ◽  
M.B. Mohamed ◽  
I.M. Azzouz
Keyword(s):  
Spontaneous Emission ◽  
Amplified Spontaneous Emission ◽  
Silica Shell ◽  
Thermal Therapy ◽  
Threshold Power ◽  
Excitation Wavelength ◽  
Exciton Absorption ◽  
Light Emitting ◽  
Cdte Nanoparticles ◽  
And Control

In this work, a hybrid nanocomposite of metal–dielectric–semiconductor, Ag–SiO2–CdTe, nanoparticles has been synthesized. Silica shell was used as a spacer to isolate and control the distance between Ag plasmonic and luminescent CdTe QDs. It was found that insertion of silica shell enhances the plasmonic field more than 31%. Accordingly, Ag-SiO2 plasmonic enhances the luminescence and quantum yield of CdTe quantum dots by 200% and 55%, respectively. The threshold power of amplified spontaneous emission of CdTe was found to depend on both temperature and excitation wavelength location with respect to plasmon and exciton absorption. This nanocomposite could be potentially used in light-emitting diodes, biological sensing, and thermal therapy.

Strong Two-Photon Excited Fluorescence and Stimulated Emission from an Organic Single Crystal of an Oligo(Phenylene Vinylene)

2009 ◽  
Vol 49 (4) ◽  
pp. 732-735 ◽  
Author(s):  
Fei Gao ◽  
Qing Liao ◽  
Zhen-Zhen Xu ◽  
Yong-Hao Yue ◽  
Qiang Wang ◽  
...  
Keyword(s):  
Single Crystal ◽  
Stimulated Emission ◽  
Phenylene Vinylene ◽  
Two Photon ◽  
Organic Single Crystal

Strong Two-Photon Excited Fluorescence and Stimulated Emission from an Organic Single Crystal of an Oligo(Phenylene Vinylene)

2009 ◽  
Vol 122 (4) ◽  
pp. 744-747 ◽  
Author(s):  
Fei Gao ◽  
Qing Liao ◽  
Zhen-Zhen Xu ◽  
Yong-Hao Yue ◽  
Qiang Wang ◽  
...  
Keyword(s):  
Single Crystal ◽  
Stimulated Emission ◽  
Phenylene Vinylene ◽  
Two Photon ◽  
Organic Single Crystal

scholarly journals Nanocrystal Quantum Dots: Building Blocks for Tunable Optical Amplifiers and Lasers

2001 ◽  
Vol 667 ◽  
Author(s):  
Jennifer A. Hollingsworth ◽  
Alexander A. Mikhailovsky ◽  
Anton Malko ◽  
Victor I. Klimov ◽  
Catherine A. Leatherdale ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Confinement ◽  
Optical Amplifiers ◽  
Optical Gain ◽  
Building Blocks ◽  
Stimulated Emission ◽  
Optical Amplification ◽  
Organometallic Reactions ◽  
Wide Range ◽  
Nanocrystal Quantum Dots

ABSTRACTWe study optical processes relevant to optical amplification and lasing in CdSe nanocrystal quantum dots (NQD). NQDs are freestanding nanoparticles prepared using solution-based organometallic reactions originally developed for the Cd chalcogenides, CdS, CdSe and CdTe [J. Am. Chem. Soc. 115, 8706 (1993)]. We investigate NQDs with diameters ranging from 2 to 8 nm. Due to strong quantum confinement, they exhibit size-dependent spectral tunability over an energy range as wide as several hundred meV. We observe a strong effect of the matrix/solvent on optical gain properties of CdSe NQDs. In most of the commonly used solvents (such as hexane and toluene), gain is suppressed due to strong photoinduced absorption associated with carriers trapped at solvent-related interface states. In contrast, matrix-free close packed NQD films (NQD solids) exhibit large optical gain with a magnitude that is sufficiently high for the optical gain to successfully compete with multiparticle Auger recombination [Science 287, 10117 (2000)]. These films exhibit narrowband stimulated emission at both cryogenic and room temperature, and the emission color is tunable with dot size [Science 290, 314 (2000)]. Moreover, the NQD films can be incorporated into microcavities of different geometries (micro-spheres, wires, tubes) that produce lasing in whispering gallery modes. The facile preparation, chemical flexibility and wide-range spectral tunability due to strong quantum confinement are the key advantages that should motivate research into NQD applications in optical amplifiers and lasers.

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