| 1. |
- Berggren, Magnus, 1968-, et al.
(författare)
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Organic laser based on lithographically defined photonic-bandgap resonators
- 1998
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Ingår i: Electronics Letters. - : IEEE. - 0013-5194 .- 1350-911X. ; 34:1, s. 90-91
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Tidskriftsartikel (refereegranskat)abstract
- The authors report the fabrication and characteristics of organic solid-state waveguide lasers with feedback from a photolithographically defined rhomboid photonic bandgap lattice. The lattice is formed by etching holes of depth 10-40 nm in SiO2 and filling them with the organic gain medium. The gain medium is part of a planar waveguide formed by air/organic layer/SiO2.
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| 2. |
- Berggren, Magnus, et al.
(författare)
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Organic solid-state lasers with imprinted gratings on plastic substrates
- 1998
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Ingår i: Applied Physics Letters. - : American Institute of Physics (AIP). - 0003-6951 .- 1077-3118. ; 72:4, s. 410-411
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Tidskriftsartikel (refereegranskat)abstract
- Optically pumped laser emission has been observed from thin films of 8-hydroxyquinolinato aluminum (Alq) doped with a DCM dye deposited on a diffraction,orating formed by imprinting a film of BCB with a mold. The BCB film, which is 4 mu m thick, is deposited on a silicon or a flexible plastic substrate. Laser emission occurs at a wavelength war 655 nm which corresponds to the third order of the grating, which has a periodicity of similar to 0.6 mu m. (C) 1998 American Institute of Physics.
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| 3. |
- Dodabalapur, A., et al.
(författare)
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Applied physics - Organic solid-state lasers : Past and future
- 1997
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Ingår i: Science. - : American Association for the Advancement of Science. - 0036-8075 .- 1095-9203. ; 277:5333, s. 1787-1788
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Researchers around the world are seeking organic materials that can be made into practical and efficient lasers. In their Perspective, Dodabalapur et al. review the past history and future prospects of this important class of laser materials.
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| 4. |
- Dodabalapur, A, et al.
(författare)
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Resonators and materials for organic lasers based on energy transfer
- 1998
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Ingår i: IEEE Journal of Selected Topics in Quantum Electronics. - : Institute of Electrical and Electronics Engineers (IEEE). - 1077-260X .- 1558-4542. ; 4:1, s. 67-74
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Tidskriftsartikel (refereegranskat)abstract
- Optically pumped lasers have been fabricated with organic/polymeric materials capable of charge transport. The active materials employed are doped films with small molecule hosts and dye, oligomer, and conjugated polymer emitters, In these materials, the excited states created in the host are transferred nonradiatively to the guest molecules which are the emitters, This energy transfer results in very low absorption losses at the emission wavelength and relatively low-threshold powers for the onset of stimulated emission. Such gain media have been successfully included in many types of resonators including whispering-gallery mode, photonic bandgap, and distributed Bragg reflector (DBR) based resonators. A number of novel patterning and fabrication procedures have been developed for organic-based lasers.
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| 5. |
- Ostrick, J. R., et al.
(författare)
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Conductivity-type anisotropy in molecular solids
- 1997
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Ingår i: Journal of Applied Physics. - : American Institute of Physics (AIP). - 0021-8979 .- 1089-7550. ; 81:10, s. 6804-6808
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Tidskriftsartikel (refereegranskat)abstract
- Thin polycrystalline films of perylenetetracarboxylic dianyhydride (PTCDA), an organic molecular solid, exhibits substantial anisotropies in its electronic transport properties. Only electrons transport in the directions along molecular planes, while mainly holes transport in the direction normal to molecular planes. A series of measurements on both field effect transistors with PTCDA active layers and light emitting diodes with PTCDA transport layers documents the anisotropy seen in the electronic transport in thin films of PTCDA. (C) 1997 American Institute of Physics.
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| 6. |
- Andersson, Martin, 1974, et al.
(författare)
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Detection of single ion channel activity on a chip using tethered bilayer membranes
- 2007
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 1520-5827 .- 0743-7463. ; 23:6, s. 2924-2927
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Tidskriftsartikel (refereegranskat)abstract
- Membrane-bound ion channels are promising biological receptors since they allow for the stochastic detection of analytes at high sensitivity. For stochastic sensing, it is necessary to measure the ion currents associated with single ion channel opening and closing events. However, this calls for stability, high reproducibility, and long lifetimes. A critical issue to overcome is the low stability of the ion channel environment, that is, the bilayer membrane. A promising technique to surmount this is to connect the lower part of the membrane to a surface forming a tethered bilayer membrane. By reconstituting the synthetic ion channel, gramicidin A, into a tethered bilayer as part of a microchip design, we have been able to record the activity of single ion channels. The observed activity was compared with that obtained by a conventional electrophysiology method, tip dipping, to confirm its authenticity. These findings allow for the construction of stable biosensors based on ion channels and provide a novel technique for the characterization of ion channel activity.
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| 7. |
- Berggren, Magnus, 1968-, et al.
(författare)
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Light amplification in organic thin films using cascade energy transfer
- 1997
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 389, s. 466-469
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Tidskriftsartikel (refereegranskat)abstract
- There is currently renewed interest in the development of lasers using solid-state organic and polymeric materials as the gain media. These materials have a number of properties that make them good candidates for such applications — for example, emission bands that are displaced (via a Stokes shift) from absorption bands, and the ease with which the emitting species can be embedded in a suitable host material1, 2, 3, 4, 5. But despite these advantages, the threshold power densities required for light amplification that have been reported so far have been high6, 7, 8. Here we describe an approach, based on energy transfer between molecular species, that can lower the threshold for stimulated emission and laser action while improving markedly the waveguiding properties of the active material. In our materials, an initial molecular excited state is generated in the host compound by absorption of light; this state is then resonantly and non-radiatively transferred down in energy (through one or more steps) between suitably matched dye molecules dispersed in the host, so ensuring that the absorption losses at the final emission wavelengths are very small. Such composite gain media provide provide broad tunability of the emission wavelength, and also decouple the optical emission properties from the transport properties, so providing greater flexibility for the design of future electrically driven device structures.
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| 8. |
- Berggren, Magnus, et al.
(författare)
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Organic lasers based on Forster transfer
- 1997
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Ingår i: Synthetic metals. - : Elsevier. - 0379-6779 .- 1879-3290. ; 91:1-3, s. 65-68
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Tidskriftsartikel (refereegranskat)abstract
- The light amplification characteristics of organic guest-host systems with Forster transfer from absorbing small molecule hosts to dye/ polymer dopants are described. Such material systems are shown to be very promising for use in low-threshold organic lasers. A number of laser resonators have been experimentally realized with Forster gain media including microdisk, ring, spheroid, and distributed Bragg reflector lasers. (C) 1997 Elsevier Science S.A.
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| 9. |
- Berggren, Magnus, et al.
(författare)
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Solid-state droplet laser made from an organic blend with a conjugated polymer emitter
- 1997
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Ingår i: Advanced Materials. - : Wiley-VCH Verlag Berlin. - 0935-9648 .- 1521-4095. ; 9:12, s. 968-
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Tidskriftsartikel (refereegranskat)abstract
- Lasers based on organic materials have been produced with a wide range of resonator design and in a variety of geometries. A new strategy is presented for fabricating permanently near-spherical whispering gallery mode (WGM) lasers from a blend of PPV7 and PBD (see Figure) by a melting and resolidification process. The thresholds and quality factors of these resonators are estimated and discussed.
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| 10. |
- Berggren, Magnus, et al.
(författare)
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Stimulated emission and lasing in dye-doped organic thin films with Forster transfer
- 1997
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Ingår i: Applied Physics Letters. - : American Institute of Physics (AIP). - 0003-6951 .- 1077-3118. ; 71:16, s. 2230-2232
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Tidskriftsartikel (refereegranskat)abstract
- Optically pumped stimulated emission and lasing in thin films of an absorbing host 8-hydroxyquinolinato aluminum(Alq) doped with small amounts of the laser dye DCM II is observed. Forster transfer of the excitation from the Alq molecules to the DCM II molecules results in a high absorption coefficient at pump wavelength (337 nm) as well as low absorption loss at the emission wavelengths (610-650 nm). (C) 1997 American Institute of Physics.
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