R. J. Tonucci

TWO-DIMENSIONAL PHOTONIC BANDGAP OPTICAL LIMITER IN THE VISIBLE

Operation of a two-dimensional photonic bandgap optical limiter was studied at 514.5 nm for pulse durations of 0.1 to 4 ms . Photonic crystals consisted of 180- 230-nm spatial-period nanochannel glasses containing a thermal nonlinear liquid. A dynamic range in excess of 130 was observed in a single-element device.

Observation of two‐dimensional photonic band behavior in the visible

Nanochannel glasses, containing regular hexagonal closed packed arrays of parallel air cylinders with periods varying from 0.25 to 0.19 μm, are shown to display photonic band‐gap behavior throughout the visible that is consistent with previously published theory. Immersing the glasses in liquids of various refractive indices allowed observation of the buildup of the bands as a function of cylinder dielectric constant.

Fabrication of GaAs and InAs wires in nanochannel glass

A newly developed porous glass, nanochannel glass, was used to fabricate uniform, high‐density GaAs and InAs micro‐ and nanowires with high aspect ratios. The fabrication process utilized reactions between organogallium and organoindium compounds with arsine to produce polycrystalline GaAs and InAs with crystallite sizes of approximately 50–130 A when annealed at 400–500 °C. At the higher annealing temperatures, the InAs wires exhibited an increase in surface porosity and grain size, whereas the GaAs wires maintained a uniform, smooth texture.

Near-infrared two-dimensional photonic band-gap materials

We describe the fabrication and optical transmission of two-dimensional periodic dielectric structures with photonic band gaps in the near infrared. The structures consist of triangular arrays of air cylinders embedded in a glass matrix, with center-to-center nearest-neighbor separations between 1.08 and 0.73 microm. The band gaps corresponding to the first Brillouin zones boundaries occur at wavelengths between 2.5 and 1.1 microm. For each array size, the band gaps along the two high-symmetry propagation directions are spectrally overlapped for light polarized perpendicular to the cylinder axes. The observed positions, widths, and polarization dependence of the band gaps are in good agreement with theoretical calculations.

Theory of probing a photonic crystal with transmission near-field optical microscopy

While near-field scanning optical microscopy ~NSOM! can provide optical images with resolution much better than the diffraction limit, analysis and interpretation of these images is often difficult. We present a theory of probing with transmission NSOM that includes the effects of tip field, tip/sample coupling, light propagation through the sample, and light collection. We apply this theory to analyze experimental NSOM images of a nanochannel glass ~NCG! array obtained in transmission mode. The NCG is a triangular array of dielectric rods in a dielectric glass matrix with a two-dimensional photonic band structure. We determine the modes for the NCG photonic crystal and simulate the observed data. The calculations show large contrast at low numerical aperture ~NA! of the collection optics and detailed structure at high NA consistent with the observed images. We present calculations as a function of NA to identify how the NCG photonic modes contribute to and determine the spatial structure in these images. Calculations are presented as a function of tip/sample position, sample index contrast and geometry, and aperture size to identify the factors that determine image formation with transmission NSOM in this experiment. @S0163-1829~98!06128-1#

Out-of-plane two-dimensional photonic band structure effects observed in the visible spectrum

We have investigated the visible-region transmission spectra of light propagating in directions which lie outside the array plane of a two-dimensional photonic crystal. These photonic crystals consist of arrays of glass rods inside a glass matrix, with periodicities comparable to the wavelengths of interest. When the propagation direction is within the array plane, attenuations corresponding to the Brillouin-zone boundaries are observed, while for out-of-plane propagation all attenuation features shift to shorter wavelengths. Interesting polarization-dependent effects appear for out-of-plane propagation.

Deep submicron pattern transfer using high density plasma etching and nanochannel glass replica technology

Nanochannel glass (NCG)‐based lithography has been used in conjunction with electron cyclotron resonance microwave plasma reactive ion etching (ECR‐RIE) to demonstrate deep submicron features in HgCdTe alloys and InAs/GaSb heterostructures. NCG‐based lithography is attractive as a massively parallel, low cost technology for nanometer‐scale patterning. Samples patterned using thin‐film metal replicas of NCG and methyl‐radical‐based ECR‐RIE demonstrate a high degree of uniformity and fidelity with individual features having nearly vertical sidewalls and aspect ratios of up to 2 to 1. Dot arrays with features as small as 250 nm (and with packing densities of ∼1010/cm2) and anti‐dot arrays with features as small as 600 nm have been realized.