| 1. |
- Balocco, C, et al.
(författare)
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Microwave detection at 110 GHz by nanowires with broken symmetry
- 2005
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 5:7, s. 1423-1427
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Tidskriftsartikel (refereegranskat)abstract
- By using arrays of nanowires with intentionally broken symmetry, we were able to detect microwaves up to 110 GHz at room temperature. This is, to the best of our knowledge, the highest speed that has been demonstrated in different types of novel electronic nanostructures to date. Our experiments showed a rather stable detection sensitivity over a broad frequency range from 100 MHz to 110 GHz. The novel working principle enabled the nanowires to detect microwaves efficiently without a dc bias. In principle, the need for only one high-resolution lithography step and the planar architecture allow an arbitrary number of nanowires to be made by folding a linear array as many times as required over a large area, for example, a whole wafer. Our experiment on 18 parallel nanowires showed a sensitivity of approximately 75 mV dc output/mW of nominal input power of the 110 GHz signal, even though only about 0.4% of the rf power was effectively applied to the structure because of an impedance mismatch. Because this array of nanowires operates simultaneously, low detection noise was achieved, allowing us to detect -25 dBm 110 GHz microwaves at zero bias with a standard setup.
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| 2. |
- Kamp, M., et al.
(författare)
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Low loss InP based photonic crystal waveguides and resonators
- 2005
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Ingår i: Optoelectronic Integrated Circuits VII. - : SPIE - International Society for Optical Engineering. - 0819457035 ; , s. 249-256
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Konferensbidrag (refereegranskat)abstract
- We report on low-loss light propagation at the communication wavelength of 1.55 μm through straight two-dimensional photonic crystal waveguides patterned into InGaAsP/InP heterostructures. The linear defect waveguides along the ΓK direction of a triangular lattice of air holes were etched deeply into the semiconductor by Cl 2/Ar electron cyclotron resonance reactive ion etching. Efficient waveguiding was observed for both polarization directions, although a photonic band gap exists for only one of the polarization states. Propagation losses, determined by the Fabry-Pérot resonance method, are as low as 0.2 dB/mm and 1.5 dB/mm for waveguides based on seven and three missing rows of holes, respectively. Waveguide resonators with 100 GHz channel spacing and quality factors up to 15,000 have been realized by inserting photonic crystal mirrors into the waveguides. The dispersion of the resonators was measured using a phase shift technique. Values for the group velocity dispersion range from -250 ps/nm to +250 ps/nm at wavelengths around 1.55 μm, which is sufficient to compensate for the dispersion of 15 km standard single-mode fiber. Controlling the device temperature allows to tune the dispersive properties of the devices.
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| 3. |
- Schuller, C., et al.
(författare)
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Polarization-dependent optical properties of planar photonic crystals infiltrated with liquid crystals
- 2005
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 87:12
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Tidskriftsartikel (refereegranskat)abstract
- Photonic crystals with infiltrated liquid crystals are investigated in the 1.5 mu m wavelength regime. Due to the strong temperature dependence of the refractive index of liquid crystals, especially near the clearing point, i.e., at the transition between nematic and isotropic phase, the optical properties of photonic crystals can be tuned by small temperature changes. The refractive index of liquid crystals is birefringent and, therefore, sensitive for the polarization of the incident light. By using microresonators embedded into planar photonic crystal waveguides, the polarization dependence of the optical properties with and without infiltrated liquid crystal is investigated. The experimental results quantitatively agree well with the calculated photonic band structure assuming a temperature depending reorientation of the liquid crystal director field inside the holes.
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| 4. |
- Zimmermann, J., et al.
(författare)
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Large dispersion in photonic crystal waveguide resonator
- 2005
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Ingår i: Electronics Letters. - : Institution of Engineering and Technology (IET). - 0013-5194 .- 1350-911X. ; 41:7, s. 414-415
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Tidskriftsartikel (refereegranskat)abstract
- Group delay and chromatic dispersion of a Fabry-Perot resonator embedded in a photonic crystal waveguide have been directly measured at 1.55 mu m avelength using the phase-shift technique. The photonic crystal waveguide resonator was fabricated in an InGaAsP/InP heterostructure and was designed to show a channel spacing of 100 GHz. Group velocity dispersion up to 250 ps/nm was observed.
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