Continuous wave mirrorless lasing in cholesteric liquid crystals with a pitch gradient across the cell gap.

Despite numerous efforts, continuous wave (CW) lasing in dye doped, one-dimensional (1D) photonic bandgap cholesteric liquid crystal (CLC) structures has not been previously reported, to our knowledge. Here we report on the observation of lasing in such structures under both coherent (laser) and incoherent (LED) CW light excitation. To achieve this effect, we used a 1D-photonic bandgap structure made of a polymer stabilized CLC with a pitch gradient across the cell thickness. A spectral reflectivity profile of such a CLC structure reveals local minima in the area within a photonic stopband and close to it. The realization of lasing pumped by low power CW light sources opens the possibility of all-organic, compact, tunable CW lasers for display and medical applications.

[1]  Hideo Takezoe,et al.  Towards highly-efficient liquid crystal microlasers , 2011, OPTO.

[2]  Timothy J White,et al.  Photoinduced hyper-reflective cholesteric liquid crystals enabled via surface initiated photopolymerization. , 2011, Chemical communications.

[3]  P. Kumar,et al.  Photon statistics of random lasers with resonant feedback. , 2001, Physical review letters.

[4]  P. Hands,et al.  Ultrafast Switching Liquid Crystals for Electro-Optic Transmissive and Reflective Displays and Microscopic Lasers , 2010 .

[5]  Peter Palffy-Muhoray,et al.  Tunable Mirrorless Lasing in Cholesteric Liquid Crystalline Elastomers , 2001 .

[6]  P Palffy-Muhoray,et al.  Ultraviolet lasing in cholesteric liquid crystals. , 2001, Optics letters.

[7]  Peter Palffy-Muhoray,et al.  Lasing in a three-dimensional photonic crystal of the liquid crystal blue phase II , 2002, Nature materials.

[8]  Jürgen Schmidtke,et al.  Fluorescence of a dye-doped cholesteric liquid crystal film in the region of the stop band: theory and experiment , 2003 .

[9]  Timothy D. Wilkinson,et al.  Red-green-blue 2 D tuneable liquid crystal laser devices , 2009, Organic Photonics + Electronics.

[10]  F. Amat-Guerri,et al.  Triplet-state spectroscopy of dipyrromethene·BF2 laser dyes , 2006 .

[11]  S. Furumi.  Recent progress in chiral photonic band-gap liquid crystals for laser applications. , 2010, Chemical record.

[12]  F. Rustichelli,et al.  On the circular dichroism and rotatory dispersion in cholesteric liquid crystals with a pitch gradient , 1976 .

[13]  K. Neyts,et al.  Liquid-crystal photonic applications , 2011 .

[14]  Peter Palffy-Muhoray,et al.  Low Threshold Lasing in Cholesteric Liquid Crystals , 2001 .

[15]  Heino Finkelmann,et al.  Defect mode emission of a dye doped cholesteric polymer network. , 2003, Physical review letters.

[16]  V. Kopp,et al.  Low-threshold lasing at the edge of a photonic stop band in cholesteric liquid crystals. , 1998, Optics letters.

[17]  Mary O'Neill,et al.  Ordered Materials for Organic Electronics and Photonics , 2011, Advanced materials.

[18]  D. J. Broer,et al.  Wide-band reflective polarizers from cholesteric polymer networks with a pitch gradient , 1995, Nature.

[19]  Stephen M. Morris,et al.  Liquid-crystal lasers , 2010 .

[20]  D. Sedrakian,et al.  Photonic band gap in 1D Photonic crystals with gradient profile of pitch and amplitude of modulation , 2007 .