Liquid crystal lasers: coherent and incoherent microsources

Morris, Stephen M.; Ford, Alison D.; Broughton, Benjamin J.; Pivnenko, Mikhail N.; Coles, H. J.

doi:10.1117/12.626460

Cited by 12 publications

(4 citation statements)

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“…The pitch can also be affected by temperature [17,18]. All samples reported here were designed to operate at a single fixed temperature of 25 °C, but it should be noted that a variation in this temperature of 10 °C, for these mixtures, corresponds to a change in emission wavelength of only approximately 5 nm.…”

Section: Sample Preparationmentioning

confidence: 99%

Polychromatic liquid crystal laser arrays towards display applications

et al. 2008

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Band-edge liquid crystal lasers are of interest for a number of applications including laser projection displays. Herein, we demonstrate simultaneous red-green-blue lasing from a single liquid crystal sample by creating a two-dimensional laser array fabricated from dye-doped chiral nematic liquid crystals. By forming a pitch gradient across the cell, and optically pumping the sample using a lenslet array, a polychromatic laser array can be observed consisting simultaneously of red-green-blue colors. Specifically, the two-dimensional polychromatic array could be used to produce a laser-based display, with low speckle and wide color gamut, whereby no complex fabrication procedure is required to generate the individual 'pixels'.

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Section: Sample Preparationmentioning

confidence: 99%

Polychromatic liquid crystal laser arrays towards display applications

et al. 2008

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“…11 This gave a Ϸ10 nm tuning range in the long bandedge wavelength by varying the cell position. 15 The locations of the optimum wavelengths were assumed to be independent of dye concentration because the shapes of the absorption and spontaneous emission spectra of the dyes were found to be approximately independent of concentration. The opt values obtained are summarized as follows: DCM opt = 609 nm, PM580 opt = 570 nm, and PM597 opt = 582 nm.…”

Section: E Optimum Laser Wavelengthmentioning

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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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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“…The alignment layers of the glass cell have the capability to enforce a strict restriction of the helix to a half integer of the pitch. This means that a small variation in the cell thickness can cause a slight change in the helix pitch at different locations of the cell [29]. As a result, In Figure 5a, a photograph of the two laser lines emitted from the cell is shown.…”

Section: Resultsmentioning

confidence: 99%

Electrically Tunable Two-Color Cholesteric Laser

Saadaoui,

Yang,

Wang

et al. 2023

Polymers

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Two-color lasing emission from an asymmetric structure, consisting of two dye-doped cholesteric liquid crystal (DD-CLC) layers separated by a transparent interlayer, is demonstrated. The DD-CLC mixtures have different reflection bands with long-wavelength band edges located at the green and red wavelengths of the visible spectrum, respectively. For the laser action, the CLC hosts provide the feedback, and the fluorescent laser dyes represent the active medium. When the stacked structure is optically pumped above the threshold, two simultaneous laser lines separated by 123 nm are observed at the long-wavelength band edges of the DD-CLC mixtures. The influence of an electric field on lasing behavior is also analyzed and discussed in terms of the reflection spectrum and laser action. The results show a reversible tuning of the reflection band, accompanied by a modification of the lasing characteristics under the application of an external field. Above a specific threshold voltage, one of the emission lines is suppressed and the other is conserved. With a further increase in the voltage, both laser emissions are entirely inhibited. The investigated structure demonstrates a simple technique to obtain an electrically tunable multi-wavelength laser, which might pave the way for a new generation of organic laser sources.

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Liquid crystal lasers: coherent and incoherent microsources

Cited by 12 publications

References 0 publications

Polychromatic liquid crystal laser arrays towards display applications

Polychromatic liquid crystal laser arrays towards display applications

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

Electrically Tunable Two-Color Cholesteric Laser

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