Real-time and low-cost sensing technique based on photonic bandgap structures

Abstract

A technique for the development of low-cost and high-sensitivity photonic biosensing devices is proposed and experimentally demonstrated. In this technique, a photonic bandgap structure is used as transducer, but its readout is performed by simply using a broadband source, an optical filter, and a power meter, without the need of obtaining the transmission spectrum of the structure; thus, a really low-cost system and real-time results are achieved. Experimental results show that it is possible to detect very low refractive index variations, achieving a detection limit below 2 × 10 −6 refractive index units using this low-cost measuring technique. , even became commercially available some years ago, devices based on integrated planar photonic structures are envisaged as a highly promising alternative for future lab-ona-chip (LoC) devices. This is due to several advantages they present compared to previously mentioned sensing technologies, such as compactness, the possibility for multianalyte detection, high sensitivity, high interaction between optical field and target analytes, shorter detection time, label-free detection, and the requirement of very low volumes to perform the sensing. Moreover, the possibility of using mass manufacturing complementary metal-oxide semiconductor techniques allows VLSI of the final devices, which results in a drastic reduction of their cost. Planar photonic sensing devices, which have been most used in the past few years, base their detection on the direct measurement of the shift of the structure's spectral response, as it occurs for ring resonators [4][5][6] or photonic crystals [7][8][9][10]. Therefore, these systems require the use of either a tunable laser source or an optical spectrum analyzer (OSA) to perform the readout of the device, making the total cost of the system significant. Moreover, sweeping times of the order of several seconds up to minutes are needed to acquire each spectrum, preventing an instantaneous observation of the interactions of the target analyte with the sensor. Other photonic structures, such as directional couplers [11] or Mach-Zehnder interferometers (MZIs) [12], which do not require tunable elements in the readout system and would thus allow a reduction in the final cost of the system, have also been proposed. However, compared to ring resonators or photonic crystals, these structures require much larger lengths in order to have enough interaction between the optical field and the target analyte, so that their integration level is limited (note that more compact designs for MZI-based sensors have been proposed [13]).In this Letter, we propose and experimentally demonstrate a new technique for the development of real-time and low-cost integrated photonic sensing devices. The sensing technique is based on using photonic bandgap (PBG) structures to perform the detection, but the PBG shift is indirectly determined by using a filtered broadband optical source as excitation instead of a tunable laser and a power meter at the output, thus significantly...

Real-time observation of antigen–antibody association using a low-cost biosensing system based on photonic bandgap structures

“…In a previous work [12], we presented a novel powerbased readout technique to perform the interrogation of photonic bandgap (PBG)-based sensing devices. The working principle of this technique is schematically illustrated in Fig.…”

Label-Free Biosensing Using Photonic Crystal Waveguides

“…2, which are not usually referred to as photonic crystal structures although they are based in the same principles as them, are also a very promising alternative for the development of integrated planar photonic biosensors (García et al, 2008;Kauppinen et al, 2009;Goddard et al, 2010;Castelló et al, 2011). When using a planar 1D periodic structure, the position of its guided bands or resonant modes is also highly dependant on the refractive index of the surrounding media, so shifts in their position can be used to perform the sensing.…”

“…SEM pictures of two planar 1D periodic structures used for sensing purposes. (a) 1D SOI holes cavity (Goddard et al, 2010); (b) 1D SOI corrugated waveguide (Castelló et al, 2011).…”

Towards Compact and High Speed Silicon Modulators

“…The sensing techniques are either based on the shift produced by the refractive index change associated with the introduction of a liquid containing proteins, molecules, or DNA on either the photonic band gap [84,85] or the position of the Fabry-Pérot fringes in the slow light regime [86].…”