Low-Threshold Amplified Spontaneous Emission in a Fluorene-Based Liquid Crystalline Polymer Blend

Kim, Y. C.; Lee, T.-W.; Park, O O.; Kim, C. Y.; Cho, H. N.

doi:10.1002/1521-4095(200105)13:9<646::aid-adma646>3.0.co;2-s

Cited by 37 publications

(13 citation statements)

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“…To date, optical gain and optically pumped lasing have been demonstrated in many families of conjugated molecules and with a wide range on different resonators [ 20 , 21 ] and a first indication of lasing effect under electrical pumping has been recently reported [ 22 ]. In particular the organic systems showing optical gain can be divided in the two big families of neat films or blends of active molecules [ 2 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 ,…”

Section: Introductionmentioning

confidence: 99%

“…About 27.4% percent of the papers instead find out the ASE threshold from the excitation density dependence of the spectral linewidth, by considering the peak Full Width at Half Maximum (FWHM), that typically shows a constant value at low excitation density, when only spontaneous emission is present, a narrowing when ASE sets in and a further constant lower value when ASE dominates. Several different criteria are used, like the excitation density at which the FWHM attains one half of the value it has at low density [ 33 , 35 , 36 , 37 , 38 ] (FWHM/2, used in 20.7% of the papers), starts to decrease (even if without a clear definition) [ 39 , 40 , 41 , 42 , 43 ] (FWHM

, 2.1%), reaches the average value between the values assumed at low and at high excitation density [ 44 , 45 ] (FWHM

, 1.5%) or as the excitation density at which the extrapolation of the data representing the FWHM decrease takes the value corresponding to the low excitation density [ 24 , 46 ] (FWHM

, 3.1%).…”

Section: Introductionmentioning

confidence: 99%

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Determination of the Best Empiric Method to Quantify the Amplified Spontaneous Emission Threshold in Polymeric Active Waveguides

2020

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Amplified Spontaneous Emission (ASE) threshold represents a crucial parameter often used to establish if a material is a good candidate for applications to lasers. Even if the ASE properties of conjugated polymers have been widely investigated, the specific literature is characterized by several methods to determine the ASE threshold, making comparison among the obtained values impossible. We quantitatively compare 9 different methods employed in literature to determine the ASE threshold, in order to find out the best candidate to determine the most accurate estimate of it. The experiment has been performed on thin films of an homopolymer, a copolymer and a host:guest polymer blend, namely poly(9,9-dioctylfluorene) (PFO), poly(9,9-dioctylfluorene-cobenzothiadiazole) (F8BT) and F8BT:poly(3- hexylthiophene) (F8BT:rrP3HT), applying the Variable Pump Intensity (VPI) and the Variable Stripe Length (VSL) methods. We demonstrate that, among all the spectral features affected by the presence of ASE, the most sensitive is the spectral linewidth and that the best way to estimate the ASE threshold is to determine the excitation density at the beginning of the line narrowing. We also show that the methods most frequently used in literature always overestimate the threshold up to more than one order of magnitude.

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Section: Introductionmentioning

confidence: 99%

, 2.1%), reaches the average value between the values assumed at low and at high excitation density [ 44 , 45 ] (FWHM

, 1.5%) or as the excitation density at which the extrapolation of the data representing the FWHM decrease takes the value corresponding to the low excitation density [ 24 , 46 ] (FWHM

, 3.1%).…”

Section: Introductionmentioning

confidence: 99%

Determination of the Best Empiric Method to Quantify the Amplified Spontaneous Emission Threshold in Polymeric Active Waveguides

2020

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“…Dye doped LC systems in comparison with commonly used polymer matrices characterize similar or even lower pumping energy thresholds 19,20 . Moreover, some examples of the obtained stimulated emission phenomena with low energy threshold observed for LC and polymer combined matrices, were reported in the literature before 21 . In the case of polymer-liquid crystal blend it was possible to obtain lower energy threshold in comparison with homogenous matrix.…”

Section: Introductionmentioning

confidence: 87%

The ultra-photostable and electrically modulated Stimulated Emission in perylene-based dye doped liquid crystal

Adamow

Sznitko

Chrzumnicka

et al. 2019

Sci Rep

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One of the most important drawback of organic dyes is their low photo-stability which reduces possibility of their commercial utilization. In this article we employ the strategy of dye re-crystallization from oversaturated matrix in order to enhance material’s durability. One of the main advantages of perylene derivative is ability to form emissive j-aggregates, good miscibility and incorporation into liquid crystalline matrix. Investigation of perylene-based dye and LC matrix brought as the result very efficient light amplification modulation by applied external electric field. In our article we show that Stimulated Emission (STE) is possible to achieve from perylene-derivative based system, at typical fluence thresholds for laser dyes: 3.9 mJ/cm2. Moreover, presented system proves ultra-high photostability, showing lack of STE reduction even after 12 000 excitation laser pulses. Furthermore, we proved the possibility of light emission intensity control using external electric field.

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“…This low efficiency is characteristic for F8DVB, which exhibits exciton–exciton quenching above threshold. [ 28–30 ] Again, thresholds for lasing in the respective input–output curve come with a sharp decrease in FWHM, which decreases at the threshold to <1 nm, indicating stimulated and amplified emission.…”

Section: Figurementioning

confidence: 99%

Narrow Stimulated Resonance Raman Scattering and WGM Lasing in Small Conjugated Polymer Particles for Live Cell Tagging and Tracking

Haehnle

Lamla

Sparrer

et al. 2020

Advanced Optical Materials

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Conjugated polymer particles are brightly fluorescing and stable materials for live cell imaging. Combination of conjugated polymers with a whispering gallery mode (WGM) resonator allows laser emission from microscale particles. Once internalized by cells, the mode pattern of the laser emission can be used for tagging and tracking, as each laser spectrum represents a bar code to identify individual cells. However, currently these particle systems are limited by their large size, which might interfere with cellular functions. Here, stimulated resonance Raman scattering (SRRS) in small conjugated polymer microparticles is presented as a new method for generating narrow emission as an alternative to WGM‐based laser emission. This opens up spectral range for multiplexing optical readout and multicolor imaging of live cells. The synthesis of monodisperse micrometer‐sized poly(fluorene‐co‐divinylbenzene) particles is discussed and their WGM and SRRS emission are characterized. Finally, how these particles and their emission can be employed in live cell imaging and tagging is showcased.

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Low-Threshold Amplified Spontaneous Emission in a Fluorene-Based Liquid Crystalline Polymer Blend

Cited by 37 publications

References 0 publications

Determination of the Best Empiric Method to Quantify the Amplified Spontaneous Emission Threshold in Polymeric Active Waveguides

Determination of the Best Empiric Method to Quantify the Amplified Spontaneous Emission Threshold in Polymeric Active Waveguides

The ultra-photostable and electrically modulated Stimulated Emission in perylene-based dye doped liquid crystal

Narrow Stimulated Resonance Raman Scattering and WGM Lasing in Small Conjugated Polymer Particles for Live Cell Tagging and Tracking

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