A Review of Single-Mode Fiber Optofluidics

Abstract

We review the field we describe as "single-mode fiber optofluidics" which combines the technologies of microfluidics with single-mode fiber optics for delivering new implementations of well-known single-mode optical fiber devices. The ability of a fluid to be easily shaped to different geometries plus the ability to have its optical properties easily changed via concentration changes or an applied electrical or magnetic field offers potential benefits such as no mechanical moving parts, miniaturization, increased sensitivity and lower costs. However, device fabrication and operation can be more complex than in established singlemode fiber optic devices. . Her research areas include optofluidic devices and applications.Deepak Uttamchandani (SM'05) received his PhD degree from University College London, London, UK in 1985 for research in the areas of optical fiber sensors and optical frequency domain reflectometry. He is currently the Head of the Centre for Microsystems and Photonics, University of Strathclyde, Glasgow, UK. His early research in MEMS concentrated on opto-thermal microresonator sensors and in investigating techniques for MEMS material characterization using micromechanical resonators. His recent research has concentrated on system applications of optical MEMS including intra-cavity MEMS-based laser systems, MEMS-based directional microphones and MEMS-based single-pixel imaging systems. He has also published in the fields of optofluidic devices, optical sensors, including sub-wavelength tipbased Raman spectroscopy, and in situ intraocular drug detection systems via optical spectroscopy in the eye. In 2014 he organized and chaired the IEEE Optical MEMS and Nanophotonics conference (Glasgow, UK)..

Femtosecond Laser Micromachining of Fabry-Pérot Interferometers for Magnetic Field Sensing

“…2, the interference spectrum shows a blue-shift when the field strength increases, indicating that the fluid's refractive index is decreasing. This is contradictory to what is expected [1][2][3][4] and can be explained by the fact that the nanoparticles are attracted towards the magnet and, consequently, they exit the cavity leading to a smaller concentration of nanoparticles and a decreasing refractive index. The low visibility of around 4 dB is due to the high optical absorption coefficient of the ferrofluid (≈20 dB per 100 µm).…”

“…Under an external magnetic field, the nanoparticles start to agglomerate in a chain-like structure oriented with the field direction, thereby changing the fluid's optical properties: refractive index, birefringence, dichroism, field-dependent transmission [1,2]. Taking advantage of this phenomenon, several fiber-based magnetic field sensors for measurement of field magnitude or orientation have been demonstrated [3][4][5].…”

Hybrid photonic-crystal fiber

“…Magnetic liquids such as ferrofluids also belong to the family of functional high-index materials as they have been used for the development of all-fiber magnetically tunable devices (Blue, Dudus, and Uttamchandani, 2016). Thakur et al (2011) infiltrated the Fe 3 O 4 nanofluid inside a polarization-maintaining solid-core PCF for the first time and they demonstrated a magnetic field sensor.…”

Optofluidic Device Based Microflow Cytometers for Particle/Cell Detection: A Review

“…Optical fibers (both single-mode fibers and multi-mode fibers) can be coupled with lasers to provide decent beam shaping at the interrogation region; however, the beam diverges as it leaves the guiding medium. Optofluidic devices coupled with single-mode fibers have been well-reviewed by Blue et al [ 53 ]. A device with an integrated on-chip lens system couples light from an optical fiber to an on-chip waveguide to deliver the light to the lens system and focuses and shapes the light in the interrogation region [ 54 , 55 ].…”