Polymer Fiber Laser Research Articles

Non-invasive imaging using a low-spatial-coherence multimode random polymer fiber laser.

Random lasers (RLs), with their low spatial coherence, are ideal illumination sources for speckle-free imaging. However, it is still challenging for RLs to maintain low spatial coherence with the need for integration and directionality. Here, a disordered multimode random polymer fiber laser (RPFL) is proposed and implemented as a low-spatial-coherence light source. Compared to typical multimode optical fibers, the number of accommodated modes is increased by about 11×, the speckle contrast is reduced to 0.013, and the spatial coherence factor is reduced to 0.08. The low-spatial-coherence property enables RPFL to produce significantly superior imaging quality in both speckle-free imaging and non-invasive imaging through opacity. This study provides a strategy for an integrated speckle-free imaging system and paves the way for non-invasive imaging.

Towards Highly Efficient Polymer Fiber Laser Sources for Integrated Photonic Sensors

Lab-on-a-Chip (LoC) devices combining microfluidic analyte provision with integrated optical analysis are highly desirable for several applications in biological or medical sciences. While the microfluidic approach is already broadly addressed, some work needs to be done regarding the integrated optics, especially provision of highly integrable laser sources. Polymer optical fiber (POF) lasers represent an alignment-free, rugged, and flexible technology platform. Additionally, POFs are intrinsically compatible to polymer microfluidic devices. Home-made Rhodamine B (RB)-doped POFs were characterized with experimental and numerical parameter studies on their lasing potential. High output energies of 1.65 mJ, high slope efficiencies of , and -lifetimes of ≥900 k shots were extracted from RB:POFs. Furthermore, RB:POFs show broad spectral tunability over several tens of nanometers. A route to optimize polymer fiber lasers is revealed, providing functionality for a broad range of LoC devices. Spectral tunability, high efficiencies, and output energies enable a broad field of LoC applications.

Silver nanoparticles filled hollow polymer fiber laser with enhanced photostability

In the present work we demonstrate multimodal laser emission characteristics from dye doped hollow polymer fiber filled with silver nanoparticle solution. The ring resonator structure was a hollow polymer fiber doped with Rhodamine B (RhB). The technique of filling metal nanoparticles inside the hollow dye doped polymer fiber laser was found to be an extremely simple method of optical feedback for lasing action. For silver nanoparticles filled structure we observe a dual threshold mechanism. An easy tuning of the system was achieved by varying the concentration of silver nanoparticles. The silver nanoparticles filled hollow polymer fiber exhibited enhanced photo-stability even at high pump powers. The Q factor achieved was greater than 6.5 × 103 in this case.

Ag nanowire-assisted low threshold WGM lasing from polymer optical fiber.

Whispering Gallery Mode (WGM) emission has been observed from Ag nanowire doped polymer optical fiber laser. Low threshold lasing and high photostability of the active medium has been noticed with a given concentration of Ag nanowires in the microcavity of the fiber. Quantum yield and lifetime measurements of the dye (active medium) with and without nanowires confirm that presence of nanowires enhance the rate of radiative decay of the fluorophore, thereby providing low pump pulse energy for the excitation of lasing modes in the cavity, as compared with a bare dye-doped polymer fiber laser.

Polarized random laser emission from an oriented disorder polymer optical fiber

We demonstrate the realization of a polarized random polymer fiber laser (RPFL) in the different disordered gain media doped polymer optical fibers (POFs). Multiple scattering of disordered media in the orientated POF was experimentally verified to account for polarized lasing observed in our RPFL system. This Letter presents a new avenue for fabricating polarized RPFLs in a large scale. Meanwhile, the polarization-maintaining property of random lasing for different disorder POF are researched, which will open a window to designing a polarization-maintaining random fiber laser.

Random lasing from dye doped polymer optical fiber containing gold nanoparticles

We have demonstrated the realization of a plasmonic random polymer fiber laser (RPFL) based on gold nanoparticles (NPs) doped one-dimensional disordered gain polymer optical fiber (POF). In this work, the plasmonic RPFL is fabricated by directly drawing from a laser dye and gold NPs system codoped POF. The random lasing can be obtained from the waveguide-plasmon-scattering in the POF system. Meanwhile, the dye doped fiber in the presence gold NPs has high photostability.

Microring embedded hollow polymer fiber laser

Strongly modulated laser emission has been observed from rhodamine B doped microring resonator embedded in a hollow polymer optical fiber by transverse optical pumping. The microring resonator is fabricated on the inner wall of a hollow polymer fiber. Highly sharp lasing lines, strong mode selection, and a collimated laser beam are observed from the fiber. Nearly single mode lasing with a side mode suppression ratio of up to 11.8 dB is obtained from the strongly modulated lasing spectrum. The microring embedded hollow polymer fiber laser has shown efficient lasing characteristics even at a propagation length of 1.5 m.

Wavelength control of random polymer fiber laser based on adaptive disorder.

We demonstrate the realization of two different kinds of random polymer optical fiber lasers to control the random lasing wavelength by changing the disorder of polymer optical fibers (POFs). One is a long-range disorder POF based on copolymer refractive-index inhomogeneity, and the other is a short-range disorder POF based on polyhedral oligomeric silsesquioxanes scattering. By end pumped both disorder POFs, the coherent random lasing for both is observed. Meanwhile, the random lasing wavelength of the short-range disorder POF because of a small scattering mean-free path has been found to be blue shifted with respect to the long-range disorder POF, which will give a way to control the random lasing wavelength.

Disordered microstructure polymer optical fiber for stabilized coherent random fiber laser

We have demonstrated the realization of a random polymer fiber laser (RPFL) based on laser dye Pyrromethene 597-doped one-dimensional disordered polymer optical fiber (POF). The stabilized coherent laser action for the disordered POF has been obtained by the weak optical multiple scattering of the polyhedral oligomeric silsesquioxanes nanoparticles in the core of the POF in situ formed during polymerization, which was enhanced by the waveguide confinement effect. Meanwhile, the threshold of our RPFL system is almost one order of magnitude lower than that of the liquid core random fiber laser reported previously, which promotes the development of random lasers.

Integrated self‐aligned conjugated polymer fiber laser devices

AbstractIn this letter we present a fully integrated self‐aligned distributed feedback (DFB) fiber laser device, which was directly imprinted in the conjugated polymer poly[2‐methoxy‐5 (2‐ethyl‐hexyloxy)‐1,4‐phenylenevinylene] (MEH‐PPV) on the top of optical fibers by using the soft lithographic technique of “liquid imprinting”. For this process master gratings (360 and 380 nm) for the feedback structure were fabricated via e‐beam lithography, transferred to an elastomeric stamp and used to imprint the grating into the highly luminescent conjugated polymer. Such second order gratings were photo‐pumped with a frequency doubled Nd:YAG laser, the laser emission (around 640 nm, depending on the used grating) was directly coupled into the waveguide and detected via a CCD spectrometer at the end of the fiber. The threshold of the laser devices was found to be in the range of 4.3 mJ/cm2 and exhibited a line width of approximately 2 nm. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Reply to comment on “Microstructured polymer fiber laser”

We have confirmed the suggestion of Gibson and Osterberg [Opt. Lett.30, 1827 (2005) ] that the lasing action observed in Rhodamine 6G-doped microstructured polymer fibers [ Argyros et al., Opt. Lett.29, 1882 (2004) ] is due to stimulated Raman scattering. The Raman scattering occurs in the poly(methyl methacrylate) host material, and upon further investigation emission up to the third Stokes order was observed. Lasing of the dye in a microstructured polymer fiber was achieved with a modification of the fiber properties.

Microstructured polymer fiber laser.

A microstructured polymer optical fiber doped with Rhodamine 6G dye was fabricated and demonstrated as an optical amplifier and a fiber laser. As an amplifier, the fiber achieved a gain in excess of 30 dB. As a pulsed fiber laser, the fiber exhibited a threshold of 20 microJ, a slope efficiency of 18%, and a lifetime as high as 130,000 shots at 10 Hz. The maximum output energy was 16 microJ. The advantages that such fibers offer lie in the simplicity and flexibility of their fabrication and in their potential for use as compact, tunable solid-state sources.

Rare-earth organic complexes for amplification in polymer optical fibers and waveguides

The optical properties of rare-earth organic complexes have been studied because of their possible application to polymer optical fibers and waveguides. Er3+, Nd3+, and Sm3+ ions are encapsulated in tetrakis(benzoyltrifluoroacetonate) and tetrakis(dibenzoylmethide) chelates, and their radiative properties are evaluated in several organic solvents. Analysis reveals that tetrakis(benzoyltrifluoroacetonate) chelates are promising dopants for use in rare-earth-doped polymer devices. These rare-earth complexes can be doped to high concentrations in polymer systems without quenching, providing the means for short-length amplification devices. Numerical simulations reveal that gains as high as and exceeding 20 dB should be realizable in rare-earth-doped polymer fiber amplifiers having lengths <60 cm. Similar calculations reveal threshold pump powers of tens of milliwatts for rare-earth-doped polymer fiber lasers.

Upconversion dye-doped polymer fiber laser

Two-photon pumped frequency upconversion cavity lasing at ∼610 nm is accomplished in a dye-doped polymer fiber system, pumped with ∼12 ns and 1.06 μm IR laser pulses. The dopant is a novel dye, trans-4-[p-(N-hydroxyethyl-N-methylamino)styryl]-N-methylpyridinium iodide, abbreviated as ASPI, which possesses a greater two-photon absorption cross section and stronger upconversion fluorescence emission compared to common commercial dyes (such as rhodamine 6G). Using a Q-switched Nd:YAG pulse laser as the pump source, cavity lasing could be achieved in a 3-cm-long ASPI-doped poly(2-hydroxyethyl methacrylate) solid fiber of 100 μm diameter. The experimental results of spectral, temporal, spatial, and input–output characteristics of the cavity lasing are presented. The slope efficiency of upconversion lasing was 0.9%.