Abstract
In this work, fabrication and testing of an optofluidic microsystem exploiting high aspect-ratio, vertical, silicon/air one-dimensional (1D) photonic crystals (PhC) are reported. The microsystem is composed of an electrochemically micromachined silicon substrate integrating a 1D PhC featuring high-order bandgaps in the near-infrared region, bonded to a glass cover provided with inlet/outlet holes for liquid injection/extraction in/out the PhC-itself. Wavelength shifts of the reflectivity spectrum of the photonic crystal, in the range 1.0–1.7 μm, induced by flow of different liquids through the PhC air gaps are successfully measured using an in-plane all-fibre setup, thanks to the PhC high aspect-ratio value. Experimental results well agree with theoretical predictions and highlight the good linearity and high sensitivity of such an optofluidic microsystem in measuring refractive index changes. The sensitivity value is estimated to be 1,049 nm/RIU around 1.55 μm, which is among the highest reported in the literature for integrated refractive index sensors, and explained in terms of enhanced interaction between light and liquid within the PhC.
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References
Barillaro G, Nannini A, Pieri F (2002a) Dimensional constraints on high aspect ratio silicon microstructures fabricated by photoelectrochemical etching. J Electrochem Soc 149(3):C180–C185
Barillaro G, Nannini A, Piotto M (2002b) Electrochemical etching in HF solution for silicon micromachining. Sens Actuators A 102(1–2):195–201
Barillaro G, Diligenti A, Benedetti M, Merlo S (2006) Silicon micromachined periodic structures for optical applications at 1.55 μm. Appl Phys Lett 89(15):151110–151113
Barillaro G, Strambini LM, Merlo S (2008) Bandgap tuning of silicon micromachined 1-D photonic crystals by thermal oxidation. IEEE J Sel Topics Quantum Electron 14(4):1074–1081
Barillaro G, Merlo S, Strambini LM (2009a) Optical characterization of alcohol-infiltrated one-dimensional silicon photonic crystals. Opt Lett 34(12):1912–1914
Barillaro G, Strambini LM, Annovazzi-Lodi V, Merlo S (2009b) Optical characterization of high-order 1-D silicon photonic crystals. IEEE J Sel Topics Quantum Electron 15(5):1359–1367
Barillaro G, Merlo S, Surdo S, Strambini LM, Carpignano F (2010) Optical quality-assessment of high-order one-dimensional silicon photonic crystals with a reflectivity notch at ≈ 1.55 μm. IEEE Photon J 2(6):981–990
Chelnokov A, David S, Wang K, Marty F, Lourtioz J-M (2002) Fabrication of 2-D and 3-D silicon photonic crystals by deep etching. IEEE J Sel Topics Quantum Electron 8(4):919–927
Chow E, Grot A, Mirkarimi LW, Sigalas M, Girolami G (2004) Ultracompact biochemical sensor built with two-dimensional photonic crystal microcavity. Opt Lett 29(10):1093–1095
De Stefano L, Rea I, Moretti L, Della Corte FG, Rotiroti L, Alfieri D, Rendina I (2007) An integrated pressure-driven microsystem based on porous silicon for optical monitoring of gaseous and liquid substances. Phys Stat Sol 204(5):1459–1463
Grillet C, Monat C, Smith CL, Lee MW, Tomlyenovic-Hanic S, Karnutsch C, Eggleton BJ (2004) Reconfigurable photonic crystal circuits. Laser Photon Rev 4(2):192–204
Gruning U, Lehmann V (1996) Two-dimensional infrared photonic crystal based on macroporous silicon. Thin Solid Films 276(1–2):151–154
Knowles KM, van Helvoort ATJ (2006) Anodic bonding. Int Mater Rev 51(5):273–311
Lee S-K, Park S-G, Moon JH, Yang S-M (2008) Holographic fabrication of photonic nanostructures for optofluidic integration. Lab Chip 8(3):388–391
Lehmann V, Foll H (1990) Formation mechanism and properties of electrochemically etched trenches in n-type silicon. J Electrochem Soc 137(2):653–659
Lehmann V (1993) The physics of macropore formation in low doped n-type silicon. J Electrochem Soc 140(2):2836–2843
Lipson A, Yeatman EM (2007) A 1-D photonic band gap tunable optical filter in (110) silicon. J Microelectromech Syst 16(3):521–527
Mandal S, Goddard JM, Erickson D (2009) A multiplexed optofluidic biomolecular sensor for low mass detection. Lab Chip 9(20):2924–2932
Mogensen KB, Kutter JP (2009) Optical detection in microfluidic systems. Electrophoresis 30(1):S92–S100 (and references within it)
Monat C, Domachuk P, Eggleton J (2007) Integrated optofluidics: a new river of light. Nat Photon 1:106–114
Monat C, Domachuk P, Grillet C, Collins M, Eggleton BJ, Cronin-Golomb M, Mutzenich S, Mahmud T, Rosengarten G, Mitchell A (2008) Optofluidics: a novel generation of reconfigurable and adaptive compact architectures. Microfluid Nanofluid 4(1-2):81–85 (and references within it)
Nunes PS, Mortensen NA, Kutter JP, Mogensen KB (2008) Photonic crystal resonator integrated in a microfluidic system. Opt Lett 33(14):1623–1625
Saadany B, Malak M, Kubota M, Marty F, Mita Y, Khalil D, Bourouina T (2006) Free-space tunable and drop optical filters using vertical bragg mirrors on silicon. IEEE J Sel Topics Quantum Electron 12(6):1480–1488
Sakoda K (2005) Optical properties of photonic crystals. Springer, Germany
Tolmachev A, Granitsyna LS, Vlasova EN, Volchek BZ, Nashchekin AV, Remenyuk AD, Astrova EV (2002) One-dimensional photonic crystal obtained by vertical anisotropic etching of silicon. Semiconductors 36(8):932–935
White IM, Fan X (2008) On the performance quantification of resonant refractive index sensors. Optics Express 16(2):1020–1028
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This research was partially supported by PRIN-MIUR and CARIPLO Foundation.
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Barillaro, G., Merlo, S., Surdo, S. et al. Integrated optofluidic microsystem based on vertical high-order one-dimensional silicon photonic crystals. Microfluid Nanofluid 12, 545–552 (2012). https://doi.org/10.1007/s10404-011-0896-0
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DOI: https://doi.org/10.1007/s10404-011-0896-0