Resonance in quantum dot fluorescence in a photonic bandgap liquid crystal host

Abstract

Microcavity resonance is demonstrated in nanocrystal quantum dot fluorescence in a one-dimensional (1D) chiral photonic bandgap cholesteric-liquid crystal host under cw excitation. The resonance demonstrates coupling between quantum dot fluorescence and the cholesteric microcavity. Observed at a band edge of a photonic stop band, this resonance has circular polarization due to microcavity chirality with 4.9 times intensity enhancement in comparison with polarization of the opposite handedness. The circular-polarization dissymmetry factor g(e) of this resonance is ~1.3. We also demonstrate photon antibunching of a single quantum dot in a similar glassy cholesteric microcavity. These results are important in cholesteric-laser research, in which so far only dyes were used, as well as for room-temperature single-photon source applications.

Quantum Dot Fluorescence in Photonic Bandgap Glassy Cholesteric Liquid Crystal Structures: Microcavity Resonance under CW-Excitation, Antibunching and Decay Time

“…In particular, we observed a circularly-polarized microcavity resonance with a bandwidth of 16 nm and a Q of ∼50 under cw-excitation [20]. These results were obtained under cw-excitation, providing the way to cw-lasing of NQDs in CLC structures.…”

“…[14][15]18] reported circularly-polarized NQD fluorescence of definite handedness due to microcavity chirality. In our paper [20] we reported for the first time significant coupling of NQD fluorescence with a CLC photonic bandgap microcavity. We observed circularly polarized microcavity resonance (strong line narrowing) on a band edge of a photonic stop band.…”

Quantum Dot/Liquid Crystal Nanocomposites in Photonic Devices

“…There are many possible liquid crystal phases, with varying degrees of positional and orientational order, but still maintaining fluid-like properties and these include the layered smectic phases, columnar phases with 2D hexagonal order and complex chiral phases such as the blue phases. The cholesteric phase, a chiral analog of the nematic phase is particularly interesting for photonic devices as it exhibits a 1D-photonic band gap in planar alignment that may be useful for lasing applications [15] and spontaneous emission enhancement in single-photon sources for secure quantum communication [16,17]. Although much more complicated, the blue phases (a 3D lattice of twisted cylinders) also exhibit photonic band gaps and have been explored for similar lasing applications.…”

Dye-doped cholesteric lasers: Distributed feedback and photonic bandgap lasing models

“…CLC lasing was obtained both in monomeric (fluid) and in glassy oligomeric (solid) liquid crystals, as well as with the addition of colloidal nanocrystal quantum dots as dopants for the CLC spontaneous emission enhancement [25] and the lasing [26] instead of dyes, which opens an opportunity of their application at telecom wavelengths of 1.3 and 1.55 ȝm.…”

“…The circular polarized single-photon sources to secure the quantum communication were proposed, by using CLC as a single-photon source of spontaneous emission with definite polarizations of single photons [30][31][32].…”