Terahertz Metamaterials on Thin Silicon Nitride Membranes
- PDF / 2,194,423 Bytes
- 7 Pages / 612 x 792 pts (letter) Page_size
- 40 Downloads / 197 Views
1077-L07-18
Terahertz Metamaterials on Thin Silicon Nitride Membranes Xomalin G. Peralta1,2, C. L. Arrington1, J. D. Williams3, A. Strikwerda4, R. D. Averitt4, W. J. Padilla5, J. F. O'Hara6, and I. Brener1,2 1 Sandia National Laboratories, P.O. Box 5800, MS1082, Albuquerque, NM, 87185 2 CINT SNL, Albuquerque, NM, 87185 3 University of Alabama, Huntsville, Huntsville, AL, 35899 4 Boston University, Boston, MA, 02215 5 Boston College, Chestnut Hill, MA, 02467 6 MPA CINT, Los Alamos National Laboratory, Los Alamos, NM, 87545 ABSTRACT The terahertz (THz) region of the electromagnetic spectrum holds promise for spectroscopic imaging of illicit and hazardous materials, and chemical fingerprinting using moment of inertia vibrational transitions. Passive and active devices operating at THz frequencies are currently a challenge, and a promising emerging technology for such devices is optical metamaterials. For example, a chem/bio sensing scheme based on the sensitivity of metamaterials to their dielectric environment has been proposed but may be limited due to the large concentration of electric flux in the substrate. In addition, there is an interest in fabricating 3D metamaterials, which is a challenge at these and shorter wavelengths due to fabrication constraints. In order to address both of these problems, we have developed a process to fabricate THz metamaterials on free-standing, 1 micron thick silicon nitride membranes. We will present THz transmission spectra and the corresponding simulation results for these metamaterials, comparing their performance with previously fabricated metamaterials on various thick substrates. Finally, we will present a scheme for implementing a 3D THz metamaterial based on stacking and possibly liftoff of these silicon nitride membranes. INTRODUCTION Metamaterials are artificial materials formed of an array of subwavelength (~ λ/10) metallic resonators within or on a dielectric or semiconducting substrate. They exhibit electromagnetic (EM) properties not readily available in naturally occurring materials [1-3], such as negative index of refraction. In addition, their response is scalable from radio [4] to optical frequencies [5]. Therefore, they have the potential to provide a scale-invariant design paradigm to create functional materials which can enhance our ability to manipulate, control, and detect EM radiation. The recent growth in the field of metamaterials is partly due to the promise of new devices that exploit these novel EM properties in all frequency ranges, including terahertz frequencies (1 THz ~ 300 µm) [6, 7]. Some of these devices require the fabrication of threedimensional metamaterials; by stacking individual layers, by creating arbitrarily curved surfaces, or a combination of both [2]. We have developed a process to fabricate THz metamaterials on large area, free-standing thin silicon nitride (Si3N4) membranes. Fabricating metamaterials on thin membranes reduces any dielectric losses due to the substrate, it eliminates the asymmetry in the fringing fields and enables t
Data Loading...
