A single-layer, planar, optofluidic Mach–Zehnder interferometer for label-free detection

Abstract

We have developed a planar, optofluidic Mach–Zehnder interferometer for the label-free detection of liquid samples. In contrast to most on-chip interferometers which require complex fabrication, our design was realized via a simple, single-layer soft lithography fabrication process. In addition, a single-wavelength laser source and a silicon photodetector were the only optical equipment used for data collection. The device was calibrated using published data for the refractive index of calcium chloride (CaCl2) in solution, and the biosensing capabilities of the device were tested by detecting bovine serum albumin (BSA). Our design enables a refractometer with a low limit of detection (1.24 × 10−4 refractive index units (RIU)), low variability (1 × 10−4 RIU), and high sensitivity (927.88 oscillations per RIU). This performance is comparable to state-of-the-art optofluidic refractometers that involve complex fabrication processes and/or expensive, bulky optics. The advantages of our device (i.e. simple fabrication process, straightforward optical equipment, low cost, and high detection sensitivity) make it a promising candidate for future mass-producible, inexpensive, highly sensitive, label-free optical detection systems.

Terahertz Interferometer for Integrated Goubau-Line Waveguides

“…Interferometers, by probing signal phases, have already been used for "Lab on Chip" devices in the optical spectrum to detect proteins or DNA hybridization [17,18]. It is, to the best of our knowledge, the first time that this concept is both experimentally realized and theoretically described in the case of integrated THz waveguides (a first proof of principle computation can be found in [19]).…”

Applications of Mach-Zehnder Interferometry to Studies on Local Deformation of Polymers Under Photocuring

“…Taking advantage of this spacious working place, MZI has been utilized for various experiments: electron interferometer functioning in high magnetic ield [3], low visualization and low measurements [4], for sensing applications [5]. Furthermore, optoluidic Mach-Zehnder interferometer for sensitive, label-free measurements of refractive index of luids was also developed [6]. The unique structure of Mach-Zehnder has also been utilized for optical communication as a modulator [7].…”

Single-mode fiber variable optical attenuator based on a ferrofluid shutter

“…From the results presented on the graph in Figure 6, it is possible to deduce the refractive index of the ferrofluid. For the interferometric setup shown in Figure 8, the relationship between the different parameters can be expressed by equation (2) [14]: (2) where n1 is the water refractive index, n2 is refractive index of the 1:30 ferrofluid, L is the length of the light path (1mm), 1, 2 are the wavelength peaks (1538 nm and 1560 nm). Using equation (2) we calculated the refractive index for the 1:30 diluted ferrofluid to be 1.439.…”