Theoretical study about the relations among coefficients of stimulated emission, spontaneous emission and absorption in indirect bandgap semiconductor

2013 ◽  
Vol 411 ◽  
pp. 52-55 ◽  
Author(s):  
José M. Escalante ◽  
Alejandro Martínez
Keyword(s):  
Spontaneous Emission ◽  
Theoretical Study ◽  
Stimulated Emission

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 Ultrafast stimulated emission microscopy of single nanocrystals

Science ◽  
2019 ◽  
Vol 366 (6470) ◽  
pp. 1240-1243 ◽  
Author(s):  
Lukasz Piatkowski ◽  
Nicolò Accanto ◽  
Gaëtan Calbris ◽  
Sotirios Christodoulou ◽  
Iwan Moreels ◽  
...  
Keyword(s):  
Excited State ◽  
Spontaneous Emission ◽  
Single Molecule ◽  
Room Temperature ◽  
Direct Detection ◽  
Excited State Absorption ◽  
Stimulated Emission ◽  
Detection Capability ◽  
Emission Signal ◽  
Carrier Population

Single-molecule detection is a powerful method used to distinguish different species and follow time trajectories within the ensemble average. However, such detection capability requires efficient emitters and is prone to photobleaching, and the slow, nanosecond spontaneous emission process only reports on the lowest excited state. We demonstrate direct detection of stimulated emission from individual colloidal nanocrystals at room temperature while simultaneously recording the depleted spontaneous emission, enabling us to trace the carrier population through the entire photocycle. By capturing the femtosecond evolution of the stimulated emission signal, together with the nanosecond fluorescence, we can disentangle the ultrafast charge trajectories in the excited state and determine the populations that experience stimulated emission, spontaneous emission, and excited-state absorption processes.

scholarly journals Observation of inhibited spontaneous emission and stimulated emission of rhodamine 6G in polymer replica of synthetic opal

1998 ◽  
Vol 73 (24) ◽  
pp. 3506-3508 ◽  
Author(s):  
K. Yoshino ◽  
S. B. Lee ◽  
S. Tatsuhara ◽  
Y. Kawagishi ◽  
M. Ozaki ◽  
...  
Keyword(s):  
Spontaneous Emission ◽  
Rhodamine 6G ◽  
Stimulated Emission ◽  
Synthetic Opal

scholarly journals Light Emission Properties of Thermally Evaporated CH3NH3PbBr3 Perovskite from Nano- to Macro-Scale: Role of Free and Localized Excitons

Nanomaterials ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 211
Author(s):  
Claudia Triolo ◽  
Maria Luisa De Giorgi ◽  
Antonella Lorusso ◽  
Arianna Cretì ◽  
Saveria Santangelo ◽  
...  
Keyword(s):  
Spontaneous Emission ◽  
Light Emission ◽  
Amplified Spontaneous Emission ◽  
Stimulated Emission ◽  
Thin Layers ◽  
Light Emitting ◽  
Macro Scale ◽  
Localized Excitons ◽  
Emitting Species

Over the past decade, interest about metal halide perovskites has rapidly increased, as they can find wide application in optoelectronic devices. Nevertheless, although thermal evaporation is crucial for the development and engineering of such devices based on multilayer structures, the optical properties of thermally deposited perovskite layers (spontaneous and amplified spontaneous emission) have been poorly investigated. This paper is a study from a nano- to micro- and macro-scale about the role of light-emitting species (namely free carriers and excitons) and trap states in the spontaneous emission of thermally evaporated thin layers of CH3NH3PbBr3 perovskite after wet air UV light trap passivation. The map of light emission from grains, carried out by SNOM at the nanoscale and by micro-PL techniques, clearly indicates that free and localized excitons (EXs) are the dominant light-emitting species, the localized excitons being the dominant ones in the presence of crystallites. These species also have a key role in the amplified spontaneous emission (ASE) process: for higher excitation densities, the relative contribution of localized EXs basically remains constant, while a clear competition between ASE and free EXs spontaneous emission is present, which suggests that ASE is due to stimulated emission from the free EXs.

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