Interdigital concept in photonic sensors based on an array of lossy mode resonances

Abstract

Multi-parameter detection is key in the domain of sensors. Here it is demonstrated that an indium tin oxide (ITO) nanocoating can be used to generate multiple lossy mode resonances (LMRs) in the optical spectrum. To achieve this, a nanocoating with a gradient in thickness is generated on the surface of a planar waveguide, permitting broadening of the LMR because the position of an LMR in the optical spectrum is directly related to the nanocoating thickness. The nanocoating with a gradient in thickness contributes multiple LMRs, each one centred at a different wavelength. With a further etching or deposition using a mask, a pattern of deposited and non-deposited regions can be created, resulting in isolation of the LMRs by preventing LMR overlap. This enables tracking of each central wavelength separately, which can be tuned through control of the gradient or nanocoating pattern. The array of LMR-based sensors is a photonics analogue to the interdigital concept in electronics, enabling multiple resonances to be used for multiparameter sensing.

Advances in sensors using lossy mode resonances

“…This is the case of what has been called interdigital photonic sensors developed by I. Dominguez et al, where up to 9 independent resonances have been reported on the same substrate [35]. If each of these 9 strips are biofunctionalized differently (see fig.…”

Compact and efficient lossy mode resonant refractive index sensor for aqueous environment

“…Transparent conducting oxide thin films and particularly indium-tin-oxide (ITO) films find their applications in integrated touch sensors for flexible OLED displays, photovoltaic cells, LCDs, optical fiber sensor, gas sensing, analysis of ionized media and opto-electrochemical label free biosensors [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. ITO films are transparent, conducting and chemically stable and can be used for integrated-optic sensing applications.…”

Lossy Mode Resonance Based Microfluidic Platform Developed on Planar Waveguide for Biosensing Applications

“…LMRs can be generated on this type of substrate and easily polarized by using a linear polarizer. It has been demonstrated that using coverslips, instead of other glass planar substrates such as slides, allows the generation of LMRs with better characteristics such as resonance depth, a more directive coupling, and even the possibility of multiparameter detection [ 13 , 14 ].…”