Large-scale synthesis of a silicon photonic crystal with a complete three-dimensional bandgap near 1.5 micrometres
Hi ahhaha,
Thought this might be a good continuation of our prior discussion of semiconductor mirrors. Never did hear back from that MIT spin off as to how they were going to deal with fabrication issues.........
I'll start everyone off easy. Here's the layman's version of this development and related work that can be found at Light Reading:
lightreading.com
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And now the real fun begins:
This article is from the Oct. 26 issue of Nature:
nature.com
Abstract:
Large-scale synthesis of a silicon photonic crystal with a complete three-dimensional bandgap near 1.5 micrometres
ALVARO BLANCO, et al.
Photonic technology, using light instead of electrons as the information carrier, is increasingly replacing electronics in communication and information management systems. Microscopic light manipulation, for this purpose, is achievable through photonic bandgap materials, a special class of photonic crystals in which three-dimensional, periodic dielectric constant variations controllably prohibit electromagnetic propagation throughout a specified frequency band. This can result in the localization of photons, thus providing a mechanism for controlling and inhibiting spontaneous light emission that can be exploited for photonic device fabrication. In fact, carefully engineered line defects could act as waveguides connecting photonic devices in all-optical microchips, and infiltration of the photonic material with suitable liquid crystals might produce photonic bandgap structures (and hence light-flow patterns) fully tunable by an externally applied voltage. However, the realization of this technology requires a strategy for the efficient synthesis of high-quality, large-scale photonic crystals with photonic bandgaps at micrometre and sub-micrometre wavelengths, and with rationally designed line and point defects for optical circuitry. Here we describe single crystals of silicon inverse opal with a complete three-dimensional photonic bandgap centred on 1.46 µm, produced by growing silicon inside the voids of an opal template of close-packed silica spheres that are connected by small 'necks' formed during sintering, followed by removal of the silica template. The synthesis method is simple and inexpensive, yielding photonic crystals of pure silicon that are easily integrated with existing silicon-based microelectronics.
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Another article from the October 26th Nature:
nature.com
Three-dimensional control of light in a two-dimensional photonic crystal slab
EDMOND CHOW, S.Y. LIN, S.G. JOHNSON, P.R. VILLENEUVE, J.D. JOANNOPOULOS, J.R. WENDT, G.A. VAWTER, W. ZUBRZYCKI, H. HOU & A. ALLEMAN
Optoelectronic devices are increasingly important in communication and information technology. To achieve the necessary manipulation of light (which carries information in optoelectronic devices), considerable efforts are directed at the development of photonic crystals—periodic dielectric materials that have so-called photonic bandgaps, which prohibit the propagation of photons having energies within the bandgap region. Straightforward application of the bandgap concept is generally thought to require three-dimensional (3D) photonic crystals; their two-dimensional (2D) counterparts confine light in the crystal plane, but not in the perpendicular z direction, which inevitably leads to diffraction losses. Nonetheless, 2D photonic crystals still attract interest because they are potentially more amenable to fabrication by existing techniques and diffraction losses need not seriously impair utility. Here we report the fabrication of a waveguide-coupled photonic crystal slab (essentially a free-standing 2D photonic crystal) with a strong 2D bandgap at wavelengths of about 1.5 µm, yet which is capable of fully controlling light in all three dimensions. These features confirm theoretical calculations on the possibility of achieving 3D light control using 2D bandgaps, with index guiding providing control in the third dimension, and raise the prospect of being able to realize unusual photonic-crystal devices, such as thresholdless lasers
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The device that has been synthesized at Kyoto University has been described here:
nature.com
Nature 407, 608 - 610 (2000) © Macmillan Publishers Ltd.
Trapping and emission of photons by a single defect in a photonic bandgap structure
SUSUMU NODA, ALONGKARN CHUTINAN & MASAHIRO IMADA
By introducing artificial defects and/or light-emitters into photonic bandgap structures, it should be possible to manipulate photons. For example, it has been predicted that strong localization (or trapping) of photons should occur in structures with single defects, and that the propagation of photons should be controllable using arrays of defects. But there has been little experimental progress in this regard, with the exception of a laser based on a single-defect photonic crystal. Here we demonstrate photon trapping by a single defect that has been created artificially inside a two-dimensional photonic bandgap structure. Photons propagating through a linear waveguide are trapped by the defect, which then emits them to free space. We envisage that this phenomenon may be used in ultra-small optical devices whose function is to selectively drop (or add) photons with various energies from (or to) optical communication traffic. More generally, our work should facilitate the development of all-optical circuits incorporating photonic bandgap waveguides and resonators.
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While Frank may have the luxury of reading downloaded white papers over the weekend, I'm afraid a trip to the college library is now on my agenda. More on this subject later.
The question is how can you call something an OADM if it only does DM? Oh, never mind.....
Best, Ray |
