Nanoimprinted circular grating distributed feedback dye laser

Abstract

The authors demonstrate an optically pumped surface emitting polymer dye laser fabricated by nanoimprint lithography. The laser is based on an organic dye hosted within a poly͑methylmethacrylate͒ matrix coated on a transparent substrate, and the laser cavity consists of a second order circular grating distributed feedback structure. The authors achieved lasing at 618 nm with 0.18 nm linewidth and 1.31 J/mm 2 pump threshold. The nanoimprinted solid-state dye laser offers a low-cost coherent light source for laboratory-on-chip spectroscopy systems. The laser also has a low pump threshold and a geometry well matched to light-emitting diode pump sources, which provide an interesting alternative for constructing portable polymer laser devices. Within recent years, the development of polymer dye lasers has progressed to higher levels of performance and functionality. The most attractive advantages of polymer dye lasers include low-cost processing, wide choice of emission wavelengths, and easy fabrication on flexible substrates. Several waveguide dye lasers have been studied with emission wavelengths ranging from ultraviolet to near infrared. 1 By simply changing the fluorophore doped in the polymer, these lasers can be used as the tunable sources for various applications including spectroscopy. 2 The one-dimensional ͑1D͒ distributed feedback ͑DFB͒ structure is a widely employed resonator geometry, and has been previously demonstrated for polymer lasers. 3 Operating characteristics can be significantly improved within two-dimensional structures. Here, we choose a circular grating distributed feedback structure to obtain low threshold operation, a well defined output beam, and vertical emission perpendicular to the device plane. Although, surface emitting circular grating lasers using semiconducting polymers have been previously demonstrated by Bauer et al. 4 and Turnbull et al., 5 their lasers were fabricated by depositing the organic gain material onto a prepatterned dielectric substrates, limiting the depth and the accuracy of the shape of the grating. For better geometric control, we choose nanoimprint lithography 6 as a direct patterning method. A hard mold is used to transfer patterns with high fidelity into target polymers, and this technique has become an attractive approach to define nanofabricated optical resonator structures. Conjugated polymer lasers fabricated by hot embossing have been studied by Lawrence et al., 7 and 1D DFB lasers based on organic oligomers using a room temperature nanoimprint method were reported by Pisignano et al. 8,9 In this letter, we report a circular grating distributed feedback laser fabricated on dye-doped poly͑methyl-methacrylate͒ ͑PMMA͒ films. The laser was fabricated on a glass substrate using a low-cost and manufacturable nanoimprint method. Surface emission lasing with single frequency at 618 nm and a linewidth of 0.18 nm was measured from the polymer dye laser exhibiting a threshold value of 1.31 J/mm 2 . The laser operation characteristics of circular grating resonator a...

Surface-emitting circular DFB, disk-, and ring-Bragg resonator lasers with chirped gratings III: gain saturation effects and above-threshold analysis

“…Wu et al were the first to experimentally realize such lasers in semiconductors [2]. More recently, organic polymers are also used as the gain medium for these lasers due to their low fabrication cost [3][4][5].…”

Surface-Emitting Circular Bragg Lasers – A Promising Next-Generation On-Chip Light Source for Optical Communications

“…With a more rigorous theoretical framework, Shams-Zadeh-Amiri et al analyzed their above-threshold properties and radiation fields (Shams-Zadeh-Amiri et al, 2000. More recently, organic polymers are also used as the gain medium for these lasers due to their low fabrication cost (Jebali et al, 2004;Turnbull et al, 2005;Chen et al, 2007). The circular gratings in the above-referenced work are designed radially periodic.…”

Thermal-nanoimprint lithography for perylenediimide-based distributed feedback laser fabrication

“…In some of them, relief gratings have been prepared over the substrate by holographic lithography [5,6], electron beam lithography (EBL) [7,8], laser interference lithography [8] or nanoimprint lithography (NIL) [9][10][11], and then the active film was deposited on top of them by spincasting [5], spin-coating [6,7,[9][10][11] or horizontal-dipping coating [8]. In other works direct patterning of the DFB structure on the active medium by UV laser interference ablation [12], two photon polymerization [13], or NIL [7,[14][15][16] processes have been performed. Among all these fabrication methods, NIL is one of the most promising technologies due to its high throughput, low-cost and high fidelity pattern transfer [17,18].…”