Biomedical subjects

D P Fussell

Publications and source records attributed to D P Fussell.

4 recordsLinked to original sources

PubMed2006

Spontaneous emission suppression via quantum path interference in coupled microcavities.

We examine theoretically the spontaneous emission rate in optical microstructures with cavity resonances that overlap in both position and frequency. Using projection techniques, we show that the spontaneous emission in such structures can be accurately described by the direct emission and quantum path interference of emission into a few discrete resonant modes, even though the exact infinite-dimensional problem involves a coupling to the continuum of radiation states. Moreover, we obtain an efficient numerical time-domain method for determining the spontaneous emission rate that incorporates these effects, including the suppression of spontaneous emission into some modes.

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PubMed2005

Two-dimensional treatment of the level shift and decay rate in photonic crystals.

We present a comprehensive treatment of the level shift and decay rate of a model line source in a two-dimensional photonic crystal (2D PC) composed of circular cylinders. The quantities in this strictly two-dimensional system are determined by the two-dimensional local density of states (2D LDOS), which we compute using Rayleigh-multipole methods. We extend the critical point analysis that is traditionally applied to the 2D DOS (or decay rate) to the level shift. With this, we unify the crucial quantity for experiment--the 2D LDOS in a finite PC--with the band structure and the 2D DOS, 2D LDOS, and level shift in infinite PC's. Consistent with critical point analysis, large variations in the level shift are associated with large variations in the 2D DOS (and 2D LDOS), corroborating a giant anomalous Lamb shift. The boundary of a finite 2D PC can produce resonances that cause the 2D LDOS in a finite 2D PC to differ markedly from the 2D LDOS in an infinite 2D PC.

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PubMed2004

Three-dimensional Green's tensor, local density of states, and spontaneous emission in finite two-dimensional photonic crystals composed of cylinders.

The three-dimensional local density of states (3D LDOS), which determines the radiation dynamics of a point-source, in particular the spontaneous emission rate, is presented here for finite two-dimensional photonic crystals composed of cylinders. The 3D LDOS is obtained from the 3D Green's tensor, which is calculated to high accuracy using a combination of a Fourier integral and the Rayleigh-multipole methods. A comprehensive investigation is made into the 3D LDOS of two basic types of PCs: a hexagonal cluster of air-voids in a dielectric background enclosed by an air-jacket in a fiberlike geometry, and a square cluster of dielectric cylinders in an air background. In the first of these, which has a complete in-plane band gap, the 3D LDOS can be suppressed by over an order of magnitude at the center of the air-voids and jumps sharply higher above the gap. In the second, which only has a TM gap in-plane, suppression is limited to a factor of 5 and occurs at the surface of the cylinders. The most striking band gap signature is the almost complete suppression of the radiation component of the 3D LDOS when the complete in-plane gap is sufficiently wide, accompanied by a burst into the radiation component above the gap.

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PubMed2003

Three-dimensional local density of states in a finite two-dimensional photonic crystal composed of cylinders.

The three-dimensional local density of states (LDOS), which determines the radiation dynamics of a point source, is presented here for a finite two-dimensional photonic crystal as a function of space and frequency. The LDOS is obtained from the dyadic Green's function, which is calculated exactly using the multipole method. Maximum suppression in the LDOS occurs at the high frequency edge of the complete two-dimensional band gap and varies smoothly about this frequency. Macroporous silicon is shown to suppress the LDOS by one order of magnitude at the center of its air pores.

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