Solvent detection using porous silicon optical waveguides

• Published in: Journal of luminescence Vol. 80; no. 1; pp. 119 - 123
• Main Authors: Arrand, H.F., Benson, T.M., Loni, A., Arens-Fischer, R., Krueger, M.G., Thoenissen, M., Lueth, H., Kershaw, S., Vorozov, N.N.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01-12-1998; Elsevier
• Subjects: Applied sciences; Circuit properties; Electric, optical and optoelectronic circuits; Electronics; Exact sciences and technology; Integrated optics; Integrated optics. Optical fibers and wave guides; Optical and optoelectronic circuits; Optical waveguide; Porous silicon; Sensor; Waveguides, couplers, and arrays; Integrated optics; Optical waveguide; Porous silicon; Sensor; Interface phenomena; Organic solvent; Loss; Silicon; Monolithic integrated circuit; Diffusion; Experimental study; Filler; Porous material
• ISSN: 0022-2313; 1872-7883
• DOI: 10.1016/S0022-2313(98)00079-9

Since the first report on the use of porous silicon as an optical waveguide medium in 1995, significant development has been made towards the understanding and applicability of such material. Here, the introduction of solvents (acetone, methanol, and propan-2-ol) into the pores is shown to dramatically reduce the loss of the waveguides, in a reversible manner. Both the magnitude and duration of this effect are sensitive to the solvent introduced. In some waveguides, for example, the measured loss (at 0.633
μm) falls by as much as 34
dB
cm
−1 on the introduction of acetone. Theoretical estimates of the effect of solvents on the interfacial scattering loss confirm this as the origin of the observed reductions. These results, combined with the fact that a substantial portion of the guided-mode field interacts with the solvent, indicate an enhanced sensitivity for sensor applications may be achievable.