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 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 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.

Threshold Energy Density for Pulsed Laser Annealing of Silicon

1980 ◽  
Vol 1 ◽  
Author(s):  
Dick Hoonhout ◽  
Frans Saris
Keyword(s):  
Energy Density ◽  
Layer Thickness ◽  
Laser Annealing ◽  
Threshold Energy ◽  
Amorphous Layer ◽  
Systematic Investigation ◽  
Laser Wavelength ◽  
Threshold Energy Density ◽  
Pulsed Laser Annealing ◽  
Disordered Layer

ABSTRACTWe have made a systematic investigation of the threshold energy density for recrystallization of ion-implanted silicon by Q-switched laser irradiation as function of thickness of the disordered layer, temperature during implantation, type and dose of implanted impurity, laser wavelength, and substrate orientation. Most results have been obtained with a Q-switched ruby laser. A linear dependence of the threshold on layer thickness (in the region of 60–300 nm) was found for arsneic-implanted silicon, but not for silicon-implanted silicon. For an amorphous layer thickness of 200 nm we found very little dependence of the threshold on type of dopant. In the case of the Nd:YAG laser, however, the lowest threshold was observed for column VI elements, the highest for column IV elements and intermediate and equal thresholds for the elements from column III and B. The influence of temperature during implantation was found to be small, but the threshold appeared to be different for (100)- and (111)- oriented substrates.

Structural and Electronic Properties of Laser Crystallized Silicon Films

1998 ◽  
Vol 536 ◽  
Author(s):  
T. Sameshima
Keyword(s):  
Energy Density ◽  
Hall Effect ◽  
Carrier Mobility ◽  
Laser Energy ◽  
Threshold Energy ◽  
Free Carrier ◽  
Silicon Films ◽  
Laser Energy Density ◽  
Threshold Energy Density ◽  
Hall Effect Measurements

AbstractFundamental properties of silicon films crystallized by a 30-ns-pulsed XeCI excimer laser were discussed. Although crystallization of 50-nm thick silicon films formed on quartz substrates occurred through laser hearing at the crystalline threshold energy density of 160 mJ/cm2, a higher laser energy density at 360 mJ/cm2 was necessary to crystallize silicon films completely. Analyses of free carrier optical absorption revealed that phosphorus-doped silicon films with a carrier density about 2×1020 cm−3 had a high carrier mobility of 20 cm2/Vs for irradiation at the crystallization threshold energy density, while Hall effect measurements gave a carrier mobility of electrical current traversing grain boundaries of 3 cm2/Vs. This suggested that the crystalline grains had good electrical properties. As the laser energy density increased to 360 mJ/cm2 and laser pulse number increased to 5, the carrier mobility obtained by the Hall effect measurements markedly increased to 28 cm2/Vs because of improvement of grain boundary properties, while the carrier mobility obtained by analysis of free carrier absorption increased to 40 cm2/Vs. A post annealing method at 190°C with high-pressure H2O vapor was developed to reduce the density of defect states. Increase of carrier mobility to 500 cm2/Vs was demonstrated in the polycrystalline silicon thin film transistors fabricated in laser crystallized silicon films.

scholarly journals Amplified Spontaneous Emission and Lasing in Lead Halide Perovskites: State of the Art and Perspectives

2019 ◽  
Vol 9 (21) ◽  
pp. 4591 ◽  
Author(s):  
Maria Luisa De Giorgi ◽  
Marco Anni
Keyword(s):  
Spontaneous Emission ◽  
State Of The Art ◽  
Amplified Spontaneous Emission ◽  
Optically Pumped ◽  
Active Materials ◽  
Active Layers ◽  
Current State ◽  
Main Development ◽  
Halide Perovskites ◽  
Lead Halide

Lead halide perovskites are currently receiving increasing attention due to their potential to combine easy active layers fabrication, tunable electronic and optical properties with promising performance of optoelectronic and photonic device prototypes. In this paper, we review the main development steps and the current state of the art of the research on lead halide perovskites amplified spontaneous emission and on optically pumped lasers exploiting them as active materials.

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