A red-green-blue random laser is fabricated on an optical fiber facet by the dip-coating method.

In this study, high-order distributed-feedback (DFB) polymer lasers were comparatively investigated. Their performance relies on multiple lasing directions and their advantages include their high manufacturing tolerances due to the large grating periods. Nine laser cavities were fabricated by spin-coating the gain polymer films onto a grating structure, which was manufactured via interference lithography that operated at the 2nd, 3rd, and 4th DFB orders. Low threshold lasing and high slope efficiency were achieved in high-order DFB polymer lasers due to the large grating groove depth and the large gain layer thickness. A high-order DFB configuration shows possible advantages, including the ability to control the lasing direction and to achieve multiple-wavelength lasers. Furthermore, our investigation demonstrates that the increase in threshold and decrease in slope efficiency with an increase in the feedback order can be limited by controlling the structural parameters.

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Lasers with multi-wavelength colloidal quantum dots (CQDs) can be achieved using complex grating structures and flexible substrate. The structure contains graduated periods and rectangular cavity fabricated through interference lithography, which acts as the distributed feedback cavity. A layer of densely packed CQD film is deposited on the cavity via spin coating technique. The performance of CQD lasers based on different distributed feedback cavities is investigated. Multi-wavelength lasing is achieved based on a flexible rectangular cavity.

Simultaneous distributed feedback (DFB) lasing and linear polarized random lasing are observed in a compound cavity, which consists of a grating cavity and a random cavity. The grating cavity is fabricated by interference lithography. A light-emitting polymer doped with silver nanoparticles is spin-coated on the grating, forming a random cavity. DFB lasing and random lasing occur when the periodic-random compound cavity is optically pumped. The directionality and polarization of the random laser are modified by the grating structure. These results can potentially be used to design integrated laser sources.