Publication:
Micromachined silicon lenses for terahertz applications

Research Projects
Organizational Units
Journal Issue
Abstract
Silicon microlenses are a very important tool for coupling terahertz (THz) radiation into antennas and detectors in integrated circuits. They can be used in a large array structures at this frequency range reducing considerably the crosstalk between the pixels. Drops of photoresist have been deposited and their shape transferred into the silicon by means of a Reactive Ion Etching (RIE) process. Large silicon lenses with a few mm diameter (between 1.5 and 4.5 mm) and hundreds of μm height (between 50 and 350 μm) have been fabricated. The surface of such lenses has been characterized using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM), resulting in a surface roughness of about ∼3 μm, good enough for any THz application. The beam profile at the focal plane of such lenses has been measured at a wavelength of 10.6 μm using a tomographic knife-edge technique and a CO2 laser.
Description
Received 4 May 2012, Available online 22 August 2013
Keywords
Citation
[1] J. Waters, et al. The earth observing system microwave limb sounder (EOS MLS) on the aura satellite IEEE Trans. Geosci. Remote Sens., 44 (2006) [2] G. Melnick, et al. The submillimeter wave astronomy satellite: science, objectives and instrument description Astron. J., 539 (2000), p. L77 [3] M. Ekstrom, et al. First Odin sub-mm retrievals in the tropical upper troposphere: humidity and cloud ice signals Atmos. Chem. Phys., 7 (2007), p. 459 [4] S. Gulkis, et al. MIRO: microwave instrument for rosetta orbiter Space Sci. Rev., 128 (2007), p. 561 [5] G.L. Pilbratt, et al. The Herschel mission, scientific objectives, and this meeting Proc. Eur. Space Agency Symp., 460 (2000), p. 13 [6] I. Mehdi, et al. Radiometer-on-a-chip: a path toward super-compact submillimeter-wave imaging arrays Proc. SPIE, 7671 (2010), p. 767105 [7] N. Llombart et al., Narrow angle lens antenna for THz applications, in: Antennas and Propagation Society International Symposium, 2009, APSURSI ’09, IEEE, 2009, pp. 1–4. [8] N.T. Gordon, C.L. Jones, D.J. Purdy Application of microlenses to infrared detector arrays Infrared Phys., 31 (1991), p. 599 [9] L. Erdmann, D. Efferenn Technique for monolithic fabrication os silicon microlenses with selectable rim angles Opt. Eng., 36 (1997), p. 1094 [10] J.M. Rico-García, L.M. Sánchez-Brea, J. Alda Application of tomographic techniques to the spatial-response mapping of antenna-coupled detectors in the visible Appl. Opt., 47 (2008) [11] Z.D. Popovic, R.A. Sprague, G.A.N. Connell Technique for monolithic fabrication of microlens arrays Appl. Opt., 27 (1988), p. 1281 [12] S.-K. Lee, M.-G. Kim, K.-W. Jo, S.-M. Shin, J.-H. Lee Monolithically integrated glass microlens scanner using a thermal reflow process J. Opt. A: Pure Appl. Opt., 10 (2008), p. 044003 [13] M. He, X.-C. Yuan, N.Q. Ngo, J. Bu, V. Kudryashov Simple reflow technique for fabrication of a microlens array in solgel glass Opt. Lett., 28 (2003), p. 731 [14] P. Young, in: Peacock (Ed.), Miscellaneous Works, vol. 1, London, 1804, pp. 149. [15] Y. Rotenberg, L. Boruvka, A.W. Neumann Determination of surface tension and contact angle from the shapes of axisymmetric fluid interfaces J. Colloid Interface Sci., 93 (1983), p. 169 [16] J.C. Earnshaw, E.G. Johnson, B.J. Carrol, P.J. Doyle The drop volume method for interfacial tension determination: an error analysis J. Colloid Interface Sci., 177 (1996), p. 150 [17] http://www.nanotec.com. [18] A.H. Firester, M.E. Heller, P. Sheng ”Knife-edge scanning measurements of subwavelength focused light beams Appl. Opt., 16 (1977), p. 1971 [19] S. Quabis, R. Dorn, M. Eberler, O. Glöckl, G. Leuchs The focus of light-theoretical calculation and experimental tomographic reconstruction Appl. Phys., 72 B (2001), p. 109 [20] R. Dorn, S. Quabis, G. Leuchs The focus of light – linear polarization breaks the rotational symmetry of the focal spot J. Mod. Opt., 50 (2003), p. 1917 [21] R. Dorn, S. Quabis, G. Leuchs Sharper focus for a radially polarized light beam Phys. Rev. Lett., 91 (2003), p. 233901 [22] P. Marchenko, S. Orlov, C. Huber, P. Banzer, S. Quabis, U. Peschel, G. Leuchs Interaction of highly focused vector beams with a metal knife-edge Opt. Express, 19 (2011), p. 7244
Collections