Fluorescence of a dye-doped cholesteric liquid crystal film in the region of the stop band: theory and experiment

Schmidtke, Jürgen; Stille, W.

doi:10.1140/epjb/e2003-00022-x

Cited by 165 publications

(95 citation statements)

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“…It is worth reminding that, for the high enough positive values 0.5 1 S   , Ref. [10] predicts the lowest pumping threshold just for the laser line located at the long-wavelength PhBG edge. The laser line of the lowest threshold is expected to be at the short-wavelength edge of the PhBG for still lower S values.…”

Section: Resultsmentioning

confidence: 93%

Dot lasers: isotropic droplets in a cholesteric matrix, and vice versa

Dudok¹,

Savaryn²,

Fechan³

et al. 2014

Ukr. J. Phys. Opt.

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Abstract. We have measured lasing spectra from dye-doped droplets of an isotropic liquid located in a cholesteric matrix ('inverted' suspension) and an 'inverse' system, dye-doped cholesteric droplets in an isotropic liquid ('conventional' suspension), with the both systems involving the same cholesteric and isotropic liquid components. For the conventional suspension, we have collected the lasing spectra for about 200 droplets and found that the lasing lines are clearly separated into three groups located at the short-wavelength and long-wavelength edges of a photonic band gap (PhBG) and inside the PhBG. The latter ('forbidden') line is observed for all of the droplets under examination. Occasionally, it can coexist with one or both of the lines located at the short-or/and long-wavelength PhBG edges. We have shown for the first time that, for the inverted isotropic droplets in the cholesteric matrix, a single lasing line is located at the short-wavelength PhBG edge. This reveals a PhBG-nature of that line and corresponds to a zero scalar orientational order parameter for the dye molecules placed in the isotropic liquid.

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Section: Resultsmentioning

confidence: 93%

Dot lasers: isotropic droplets in a cholesteric matrix, and vice versa

Dudok¹,

Savaryn²,

Fechan³

et al. 2014

Ukr. J. Phys. Opt.

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show abstract

“…In any real samples S d is far from these extreme values and we have 0  S d < 1 in the most of cases. If 0  S d < 1, the theory [28] shows that the polarization is circular, with the same handedness as that of the ChLC helix for the both laser modes observed at the two PhBG edges   and   .…”

Section: Lasing In Liquid Crystalsmentioning

confidence: 89%

“…At the both PhBG edges, the light wave suffering the selective reflection becomes linearly polarized. The directions of the linear polarizations are parallel and perpendicular to the local director respectively at the two PhBG edges [27,28]. For conventional thermotropic nematics with rod-like molecules we have ).…”

Section: Lasing In Liquid Crystalsmentioning

confidence: 99%

“…The polarization of this mode varies across the PhBG from the linear at one PhBG edge, through elliptical and circular, to the perpendicular linear at the opposite edge. However, to tell the truth, the values   and   that mark the PhBG edges as defined above are only first approximations of the exact values given by the theory developed by de Vrie (see [27,28]). If the ChLC is a gain medium or is doped with an appropriate dye, the stop-band lasing can be observed at the both PhBG edges but their pumping-intensity thresholds are not the same.…”

Section: Lasing In Liquid Crystalsmentioning

confidence: 99%

“…% nematic E7 (from Merk) doped with 1 wt % of a dye DG-56 Ref. [28], for an ideal case S d = 1 describing the perfect orientation (  d n ), the lowest pumping threshold corresponds to the laser mode located at the long-wavelength side   of the PhBG, while its polarization is expected to be circular, having the same handedness as that of the ChLC helix. If the second mode at the short-wavelength side   could be observed at higher pumping intensities, then its polarization would be also circular, though with the handedness opposite to that of the ChLC helix.…”

Section: Lasing In Liquid Crystalsmentioning

confidence: 99%

See 2 more Smart Citations

Optically pumped mirrorless lasing. A Review. Part II. Lasing in photonic crystals and microcavities

Dudok¹,

Nastishin²

2014

Ukr. J. Phys. Opt.

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Abstract. This article is a second part of the review on optically pumped mirrorless lasing. Consideration of random lasing presented in the first part [Nastishin Yu A and Dudok T H, 2013. Ukr. J. Phys. Opt.] is now followed by analysis of the literature on the lasing in photonic structures, which is mainly focussed on dye-doped cholesteric liquid crystals and microcavities, including liquid-crystal microdroplets.

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Liquid Crystal Lasers

Takezoe

2012

Liquid Crystals Beyond Displays

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Fluorescence of a dye-doped cholesteric liquid crystal film in the region of the stop band: theory and experiment

Cited by 165 publications

References 0 publications

Dot lasers: isotropic droplets in a cholesteric matrix, and vice versa

Dot lasers: isotropic droplets in a cholesteric matrix, and vice versa

Optically pumped mirrorless lasing. A Review. Part II. Lasing in photonic crystals and microcavities

Liquid Crystal Lasers

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