Theory and characteristics of holographic polymer dispersed liquid crystal transmission grating with scaffolding morphology

Low-threshold distributed feedback laser based on holographic polymer dispersed liquid crystals through the oriented organic semiconductor films

A specific optimized configuration for low threshold organic semiconductor laser based on a holographic polymer dispersed liquid crystal (HPDLC) transmission grating was demonstrated. Here the organic semiconductor films and phase separated liquid crystal (LC) molecules were oriented along the direction of the HPDLC grating grooves. The influence of the organic semiconductor chain orientation and the excitation polarization on the optical properties of the materials has been investigated. Especially, when polymer chain orientation, LC molecules and pump light polarization are consistent with the direction of the grating grooves, the performance of the outgoing laser is greatly improved. Up to 9.78% conversion efficiency with a threshold lower to 0.12 μJ/pulse can be obtained, indicating their potential for high-performance organic optoelectronics.

Light-Controlled Direction of Distributed Feedback Laser Emission by Photo-Mobile Polymer Films

We report on the realization of Distributed Feedback (DFB) lasing by a high-resolution reflection grating integrated in a Photomobile Polymer (PMP) film. The grating is recorded in a recently developed holographic mixture basically containing halolakanes/acrylates and a fluorescent dye molecule (Rhodamine 6G). The PMP-mixture is placed around the grating spot and a subsequent curing/photo-polymerization process is promoted by UV-irradiation. Such a process brings to the simultaneous formation of the PMP-film and the covalent link of the PMP-film to the DFB-grating area (PMP-DFB system). The PMP-DFB allows lasing action when optically pumped with a nano-pulsed green laser source. Moreover, under a low-power light-irradiation the PMP-DFB bends inducing a spatial readdressing of the DFB-laser emission. This device is the first example of a light-controlled direction of a DFB laser emission. It could represent a novel disruptive optical technology in many fields of Science, making feasible the approach to free standing and light-controllable lasers.

Classical photopolymerization kinetics, exceptional gelation, and improved diffraction efficiency and driving voltage in scaffolding morphological H-PDLCs afforded using a photoinitibitor

Ketyl radical inhibition results in prolonged gelation and an enhanced diffraction efficiency, allowing for the facile fabrication of colored 3D images.