Measurement setup to determine lasing spectrum and threshold.
(a) Measured output pulse energy vs. input pulse energy for a 20 μm CLC cell filled with mixture 2. (b) Measured laser and transmission spectrum of a CLC 20 μm cell filled with mixture 2.
(a) Polarized emission spectrum from DCM in a nematic reference cell. (b) Imaginary part (determining absorption) of the refractive indices for DCM, measured in a 6.8 μm nematic reference cell (0.98%/99.02% by weight of DCM/E7).
Reflective properties for circularly polarized light with wavelength in the photonic band gap onto a CLC film with right-handed helicity. Dots and crosses are used to visualize the helical rotation of the LC director.
Reflection of incoming e- and o-waves onto a CLC layer that is approximated by a stack of homogeneous thin anisotropic layers.
Definition of the round trip gain inside a CLC film. For reasons of clarity, the CLC is separated into two parts, and a space is introduced in the middle to illustrate the waves that are propagating in the structure.
Measured and simulated input pulse energy threshold for lasing as a function of the pitch of the CLC device for two devices with different CLC layer thicknesses.
(a) Simulated threshold coupling factor as a function of the lasing wavelength for both sides of the band edge compared to the inverse of the dye emission spectrum. (b) Simulated threshold coupling factor for different dipole orientations as a function of the CLC pitch.
Composition of liquid crystal/chiral dopant/laser dye mixtures. Different concentrations of chiral dopant are used to create CLC films with different .
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