Fabrication of 2-D and 3-D Photonic Band-Gap Crystals in the GHz and THz Regions (original) (raw)

Double-etch geometry for millimeter-wave photonic band-gap crystals

Applied Physics Letters, 1994

We have designed and developed a new double-etch technique for fabricating three-dimensional millimeter-wave photonic band-gap crystals. This technique doubles the band-gap frequency obtainable from silicon wafers. By introducing overetching, the double-etch geometry allows one-way tuning of the midgap frequency. We have experimentally demonstrated this property by fabricating and testing structures with different overetch ratios. Terahertz spectroscopy techniques were used to measure photonic band-gap crystals with midgap frequencies ranging from 340 to 375 GHz.

Micromachined millimeter-wave photonic band-gap crystals

Applied Physics Letters, 1994

We have developed a new technique for fabricating three-dimensional photonic band-gap crystals. Our method utilizes an orderly stacking of micromachined (110) silicon wafers to build the periodic structure. A structure with a full three-dimensional photonic band gap centered near 100 GHz was measured, with experimental results in good agreement with theoretical predictions. This basic approach described should be extendable to build structures with photonic band-gap frequencies ranging from 30 GHz to 3 THz.

Photonic band gap studies on periodic metallic structures in the microwave region

Microwave and Optical Technology Letters, 2002

We present our experimental findings on microstrip-type metallic photonic band gap (PBG) periodic structures prepared using a commercial aluminum foil. Effect of change in geometry of the periodic dielectric structure, namely, period, rectangular hole length, and defect on PBG, is studied. It is found that as the rectangular-hole-cut dimension decreases in terms of length, the lower edge of the band gap decreases toward the lower frequency side of the microwave region. It is also observed that as the defect length increases, the band gap edge again shifts toward the lower frequency side. These findings of band gap with air as substrate confirm the role of wave impedance in purely metallic periodic structures.

Investigation of Millimeter Wave Parametric Generation from a THz Photonic Band Gap Device

2006 IEEE Aerospace Conference, 2006

We present 1,2 a photonic band gap (PBG) structure design for terahertz (THz) wave parametric generation, which has crystal layer fabrication tolerance of a few micrometers and can be made with traditional polishing methods. This PBG structure consists of two component materials with a small refractive index difference at near infrared pump wavelengths and a large refractive index difference for THz waves. With this design the PBG device has optical properties very close to that of a bulk crystal in the near infrared, but photonic crystal features in the THz range, such as structural dispersion, which allows placement of the phase matched pump wavelength in the near infrared to eliminate two-photon absorption of the pump and signal beams. The added design flexibility also allows the use of the most efficient crystal orientations. Potential applications of this THz PBG structure are discussed.

Design of three‐dimensional photonic crystals at submicron lengthscales

Applied Physics Letters, 1994

We present a new class of periodic dielectric structures designed specifically to be amenable for fabrication at submicron lengthscales. The structures give rise to a sizable 3D photonic band gap and can be fabricated with materials widely used today in optoelectronic devices. They are made of three materials and consist essentially of a layered structure in which a series of cylindrical air holes are etched at normal incidence through the top surface of the structure. Our results demonstrate the existence of a gap as large as 14% of the midgap frequency using Si, SiO,, and air, and 23% using Si and air.

Investigation of geometry-dependent field properties of 3D printed metallic photonic crystals

arXiv (Cornell University), 2020

One terahertz (THz) waveguide based on 3D printed metallic photonic crystals is experimentally and numerically demonstrated in 0.1-0.6 THz, which consists of periodic metal rod arrays (MRAs). Results demonstrated that such waveguide supports two waveguide modes such as fundamental and high-order TM-modes. The high-order TM-mode shows high field confinement, and it is sensitive to the geometry changes. By tuning the metal rod interspace, the spectral positions, bandwidths, and transmittances of the high-frequency band can be optimized. The investigation shows that a mode conversion between high-order modes occurs when the MRAs symmetry is broken via change the air interspace.

Photonic band gaps with layer‐by‐layer double‐etched structures

Journal of Applied Physics, 1996

Periodic layer-by-layer dielectric structures with full three-dimensional photonic band gaps have been designed and fabricated. In contrast to previous layer-by-layer structures the rods in each successive layer are at an angle of 70.5°to each other, achieved by etching both sides of a silicon wafer. Photonic band-structure calculations are utilized to optimize the photonic band gap by varying the structural geometry. The structure has been fabricated by double etching Si wafers producing millimeter wave photonic band gaps between 300 and 500 GHz, in excellent agreement with band calculations. Overetching this structure produces a multiply connected geometry and increases both the size and frequency of the photonic band gap, in very good agreement with experimental measurements. This new robust double-etched structure doubles the frequency possible from a single Si wafer, and can be scaled to produced band gaps at higher frequencies.

Photonic band gap materials for devices in the microwave domain

IEEE Transactions on Magnetics, 1998

Materials with a periodically structured dielectric constant may exhibit forbidden p h o t o n i c band gaps (PBG), that is, frequency domains where electromagnetic fields cannot propagate. The position and width of forbidden gaps can b e controlled via the geometrical parameters of t h e structures and the contrast between the different permittivities. PBG materials have potential applications to a variety of devices in t h e microwave domain such as waveguides, couplers, reflectors and antenna substrates. This work reports on first experimental and theoretical studies o f microwave guides and ring couplers based on PBG materials. Experiments are performed in the 2 7-75GHz frequency range. Different c o u p l i n g situations are given in illustration.

Photonic Band Gap Materials – Theory, Techniques and Applications

— Photonic Band Gap (PBG) materials are a relatively new frontier for research that allow for control of the propagation of EM waves in desired directions and at desired frequencies. The PBG materials essentially have periodic refractive index in one-, two-, or three-dimensions in the order of wavelength of the EM wave. These PBG materials take advantage of the interaction of Photons with the periodicity of the dielectric materials. Due to periodic nature certain band gap exists in the material and photons at frequencies corresponding to the band gap (or stop band) are forbidden to pass through the material. After its inception almost three decades back, extensive research has been carried out in this domain and various structures have been proposed that are able to interact with light at Photon level and produce astonishing results. They are also a perfect solution for high-frequency operation since metallic waveguides tend to be lossy at higher (especially optical) frequencies. In this paper, a review shall be presented encompassing important aspects of PBG materials including their structures, properties, potential applications, available tools for their analysis and future research trends.