Mike P. C. Taverne

Efficient out-coupling and beaming of Tamm optical states via surface plasmon polariton excitation

We present evidence of optical Tamm states to surface plasmon polariton (SPP) coupling. We experimentally demonstrate that for a Bragg stack with a thin metal layer on the surface, hybrid Tamm-SPP modes may be excited when a grating on the air-metal interface is introduced. Out-coupling via the grating to free space propagation is shown to enhance the transmission as well as the directionality and polarization selection for the transmitted beam. We suggest that this system will be useful on those devices, where a metallic electrical contact as well as beaming and polarization control is needed.

Evidence of near-infrared partial photonic bandgap in polymeric rod-connected diamond structures

We present the simulation, fabrication, and optical characterization of low-index polymeric rod-connected diamond (RCD) structures. Such complex three-dimensional photonic crystal structures are created via direct laser writing by two-photon polymerization. To our knowledge, this is the first measurement at near-infrared wavelengths, showing partial photonic bandgaps for this structure. We characterize structures in transmission and reflection using angular resolved Fourier image spectroscopy to visualize the band structure. Comparison of the numerical simulations of such structures with the experimentally measured data show good agreement for both P- and S-polarizations.

Investigation of defect cavities formed in three-dimensional woodpile photonic crystals

We report the optimization of optical properties of single defects in three-dimensional (3D) face-centered-cubic (FCC) woodpile photonic crystal (PC) cavities by using plane-wave expansion (PWE) and finite-difference time-domain (FDTD) methods. By optimizing the dimensions of a 3D woodpile PC, wide photonic band gaps (PBG) are created. Optical cavities with resonances in the bandgap arise when point defects are introduced in the crystal. Three types of single defects are investigated in high refractive index contrast (gallium phosphide–air) woodpile structures, and Q-factors and mode volumes (Veff) of the resonant cavity modes are calculated. We show that, by introducing an air buffer around a single defect, smaller mode volumes can be obtained. We demonstrate high Q-factors up to 700,000 and cavity volumes down to Veff<0.2(λ/n)3. The estimates of Q and Veff are then used to quantify the enhancement of spontaneous emission and the possibility of achieving strong coupling with nitrogen-vacancy (NV) color centers in diamond.

FDTD Simulation of Inverse 3-D Face-Centered Cubic Photonic Crystal Cavities

We present the modeling and simulation of 3-D face-centered cubic photonic crystal (PhC) cavities with various defects. We use the plane-wave expansion method to map the allowed modes and photonic bandgaps. Having determined the photonic bands we design specific defects and input-output waveguides and model the coupling between defects and waveguides using the 3-D finite-difference time-domain method. We have calculated the Q-factors and modal volumes (Veff) of the resonant cavity modes for the PhC structures made of materials including germanium (Ge), silicon (Si), gallium phosphide (GaP), titanium dioxide (TiO2), and silica (SiO2). We then use our estimates of Q and Veff to quantify the enhancement of spontaneous emission and possibility of achieving strong coupling with color centers and quantum dots.

Modelling defect cavities formed in inverse three-dimensional rod-connected diamond photonic crystals

Defect cavities in 3D photonic crystal can trap and store light in the smallest volumes allowable in dielectric materials, enhancing non-linearities and cavity QED effects. Here, we study inverse rod-connected diamond (RCD) crystals containing point defect cavities using plane-wave expansion and finite-difference time domain methods. By optimizing the dimensions of the crystal, wide photonic bandgaps are obtained. Mid-bandgap resonances can then be engineered by introducing point defects in the crystal. We investigate a variety of single spherical defects at different locations in the unit cell focusing on high-refractive-index-contrast (3.3:1) inverse RCD structures; quality factors (Q-factors) and mode volumes of the resonant cavity modes are calculated. By choosing a symmetric arrangement, consisting of a single sphere defect located at the center of a tetrahedral arrangement, mode volumes < 0.06 cubic wavelengths are obtained, a record for high-index cavities.

Direct wide-angle measurement of a photonic band structure in a three-dimensional photonic crystal using infrared Fourier imaging spectroscopy

We propose a method to directly visualize the photonic band-structure of micrometer-sized photonic crystals using wide-angle spectroscopy. By extending Fourier imaging spectroscopy sensitivity into the infrared range, we have obtained accurate measurements of the band structures along the high-symmetry directions (X-W-K-L-U) of polymeric three-dimensional, rod-connected diamond photonic crystals. Our implementation also allows us to record single-wavelength reflectance far-field patterns showing very good agreement with simulations of the same designs. This technique is suitable for the characterization of photonic structures working in the infrared and, in particular, to obtain band-structure information of complete photonic band gap materials.

Full photonic band-structure measurement of a three-dimensional photonic crystal using infrared fourier imaging spectroscopy

Photonic crystals (PhCs) provide light trapping properties that allow people to control the flow of light, and three dimensional PhCs have been proposed as the most efficient light trapping microstructures [1]. The photonic band structure is the most important optical property of a PhC, which describes the dispersion relation for propagating modes within the structure. By measuring the bandstructure one can obtain an accurate description of the optical performance of a PhC [2]. In this case we proposed a method based on the Fourier Imaging Spectroscopy [3] (FIS) to visualize the bandstructure of a 3D-PhC microstructure in the near infrared wavelength range. This setup has potential to work at any wavelength and could be engineered into a fully portable device.

Investigation of defect cavities formed in inverse three-dimensional rod-connected diamond photonic crystals

We report the optical properties of single defects in inverse three-dimensional (3D) rod-connected diamond (RCD) photonic crystal (PhC) cavities by using plane-wave expansion (PWE) and finite-difference time domain (FDTD) methods. By optimizing the dimensions of a 3D inverse RCD PhC, wide photonic band gaps (PBG) are obtained. Optical cavities with resonances in the bandgap arise when point defects are introduced in the crystal. A variety of shapes and locations of single defects are investigated in high-refractive-index contrast (gallium phosphide-air or chalcogenide-air) inverse RCD structures, and Q-factors and mode volumes (Veff) of the resonant cavity modes are calculated. By choosing a single sphere defect located at the center of a tetrahedral arrangement, small mode volumes can be obtained. Here, high Q-factors up to 724,000 and cavity mode volumes down to Veff <; 0.3(λ/n)3 have been demonstrated.

Air/polymer microcavities inspected by Fourier image spectroscopy

This paper presents the fabrication, simulation and measurement of low refractive index micropilar/microcavity structures where the optical properties are retrieved by white light Fourier image spectroscopy. This paper aims to show with these results that organic micropillars and low refractive index cavities in 3D photonic crystals could be a suitable platform for organic based emitting devices. This paper will show that the Fourier image spectroscopy technique allows measurement of, not just the dispersion relation of the microcavity modes, but also the numerical aperture of micropillars. As a test for the characterization technique, measurements performed on AlAs/GaAs micropillars are presented.