Lasing Thresholds of Cholesteric Liquid Crystals Lasers

Cao, Wenyi; Palffy‐Muhoray, Peter; Taheri, Bahman; Marino, Antigone; Abbate, Giancarlo

doi:10.1080/15421400590930782

Cited by 63 publications

(28 citation statements)

References 19 publications

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“…8. This is in accordance with previous studies, where optimization of the dye concentration has been shown to increase the emission intensities [29][30][31] and reduce the threshold energies 28,30 of N ‫ء‬ LC lasers. The most striking feature is that the efficiencies of the PM597 lasers were always higher than those of the two other laser samples, irrespective of dye concentration.…”

Section: Discussionsupporting

confidence: 81%

“…It is important to mention that Cao et al 28 also studied the lasing thresholds of DCM-doped N ‫ء‬ LC laser samples, using a chiral nematic liquid crystalline host ͑BLO61, EM industries͒ diluted with a nematic ͑E7, EM industries͒. The range of dye concentrations used here corresponds to their intermediate concentration regime ͑0.25-2.5 wt % DCM͒, where they found that E th increased linearly with increasing DCM concentration.…”

Section: Discussionmentioning

confidence: 99%

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Comparison of the performance of photonic band-edge liquid crystal lasers using different dyes as the gain medium

Mowatt

Morris

Song

et al. 2010

Journal of Applied Physics

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The primary concern of this work is to study the emission characteristics of a series of chiral nematic liquid crystal lasers doped with different laser dyes ͑DCM, pyrromethene 580, and pyrromethene 597͒ at varying concentrations by weight ͑0.5-2 wt %͒ when optically pumped at 532 nm. Long-wavelength photonic band-edge laser emission is characterized in terms of threshold energy and slope efficiency. At every dye concentration investigated, the pyrromethene 597-doped lasers exhibit the highest slope efficiency ͑ranging from 15% to 32%͒ and the DCM-doped lasers the lowest ͑ranging from 5% to 13%͒. Similarly, the threshold was found to be, in general, higher for the DCM-doped laser samples in comparison to the pyrromethene-doped laser samples. These results are then compared with the spectral properties, quantum efficiencies and, where possible, fluorescence lifetimes of the dyes dispersed in a common nematic host. In accordance with the low thresholds and high slope efficiencies, the results show that the molar extinction coefficients and quantum efficiencies are considerably larger for the pyrromethene dyes in comparison to DCM, when dispersed in the liquid crystal host.

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Section: Discussionsupporting

confidence: 81%

Section: Discussionmentioning

confidence: 99%

Comparison of the performance of photonic band-edge liquid crystal lasers using different dyes as the gain medium

Mowatt

Morris

Song

et al. 2010

Journal of Applied Physics

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“…Cao et al studied the lasing thresholds of cholesteric liquid crystal lasers as a function of dye concentration and of sample thickness [33]. Figure 3 shows the threshold dependence on dye concentration.…”

Section: Lasing In Dye Doped Cholesteric Liquid Crystalmentioning

confidence: 99%

Lasing Characteristics of Dye-Doped Cholesteric Liquid Crystal

Porov¹,

Chandel²,

Manohar³

2015

Transactions on Electrical and Electronic Materials

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Cholesteric liquid crystals naturally form helical structures with the helical pitch in an optical wavelength range [7]. The dye and cholesteric liquid crystal molecules are together subjected to the electric field action, which produces a collective movement that leads to changes in molecular arrangement, notably the applied electric field direction. As a result of the applied field, the helical molecular arrangement axis is perpendicular to the electric field direction and then produces an increase in the helical structure pitch [8,9].A cholesteric liquid crystal can be considered as a one-dimensional photonic crystal with a refractive index that is regularly modulated along the helix axis because of the particular arrangement of the molecules. The result is that the propagation of light is suppressed for a particular range of wavelength [10]. Preeti Porov† and Vishal Singh Chandel Department of Physics, Integral University, Lucknow 226026, IndiaReceived January 8, 2015; Revised April 9, 2015; Accepted May 3, 2015Cholesteric liquid crystals are one dimensional photonic band-gap materials due to their birefringence and periodic structure. Dye doped cholesteric liquid crystals are self-assembling, mirror-less, low threshold laser structures that exhibit distributed feedback. In this review paper, we have presented the development in the field of lasing characteristics of dye doped cholesteric liquid crystals.

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“…Considering the size of the p-c cavity (microwell diameter is approximately 40 µm. ), the lasing threshold in terms of total pump energy is approximately 0.73 nJ, whereas existing band-edge lasers exhibit lasing thresholds a few orders of magnitude higher [12,17,23,24]. For comparison between the p-c and p-p cavities, spectrally integrated lasing intensities from a part of the LC-filled sandwich cell without the microwell are also measured.…”

Section: Resultsmentioning

confidence: 99%

Electro-tunable liquid crystal laser based on high-Q Fabry-Pérot microcavity

et al. 2017

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Abstract:We demonstrate an electro-tunable laser based on a plano-concave (p-c) FabryPérot (FP) microcavity filled with dye-doped liquid crystal (LC) gain material. Owing to the high Q-factor of the p-c FP microcavity, the lasing threshold of the LC laser is as low as 0.58 µJ/mm 2 . The single-mode emission wavelength can be easily tuned by varying applied voltage, which induces the reconfiguration of LC molecules. Furthermore, this lasing platform operates at room temperature, thanks to the wide temperature range of the nematic LC. We believe that our LC laser is widely applicable to light sources of various micro total analysis systems. 18. M. Y. Jeong and J. Cha, "Firsthand in situ observation of active fine laser tuning by combining a temperature gradient and a CLC wedge cell structure," Opt.

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Lasing Thresholds of Cholesteric Liquid Crystals Lasers

Cited by 63 publications

References 19 publications

Comparison of the performance of photonic band-edge liquid crystal lasers using different dyes as the gain medium

Comparison of the performance of photonic band-edge liquid crystal lasers using different dyes as the gain medium

Lasing Characteristics of Dye-Doped Cholesteric Liquid Crystal

Electro-tunable liquid crystal laser based on high-Q Fabry-Pérot microcavity

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