Field Of Optofluidics Research Articles

A Perspective on the Rise of Optofluidics and the Future

In the recent past, the field of optofluidics has thrived from the immense efforts of researchers from diverse communities. The concept of optofluidics combines optics and microfluidics to exploit novel properties and functionalities. In the very beginning, the unique properties of liquid, such as mobility, fungibility and deformability, initiated the motivation to develop optical elements or functions using fluid interfaces. Later on, the advancements of microelectromechanical system (MEMS) and microfluidic technologies enabled the realization of optofluidic components through the precise manipulation of fluids at microscale thus making it possible to streamline complex fabrication processes. The optofluidic system aims to fully integrate optical functions on a single chip instead of using external bulky optics, which can consequently lower the cost of system, downsize the system and make it promising for point-of-care diagnosis. This perspective gives an overview of the recent developments in the field of optofluidics. Firstly, the fundamental optofluidic components will be discussed and are categorized according to their basic working mechanisms, followed by the discussions on the functional instrumentations of the optofluidic components, as well as the current commercialization aspects of optofluidics. The paper concludes with the critical challenges that might hamper the transformation of optofluidic technologies from lab-based procedures to practical usages and commercialization.

Optofluidic random laser

Random lasing is reported in a dye-circulated structured polymeric microfluidic channel. The role of disorder, which results from limited accuracy of photolithographic process, is demonstrated by the variation of the emission spectrum with local-pump position and by the extreme sensitivity to a local perturbation of the structure. Thresholds comparable to those of conventional microfluidic lasers are achieved, without the hurdle of state-of-the-art cavity fabrication. Potential applications of optofluidic random lasers for on-chip sensors are discussed. Introduction of random lasers in the field of optofluidics is a promising alternative to on-chip laser integration with light and fluidic functionalities.

Optofluidics: A Light Stream Interface

Through the burgeoning field of optofluidics, researchers are using fluids to create adaptive optical systems at the microscopic scale, with applications in biophotonics, information processing and sensing.

Optical detection in microfluidic systems

Optical detection schemes continue to be favoured for measurements in microfluidic systems. A selection of the latest progress mainly within the last two years is critically reviewed. Emphasis is on integrated solutions, such as planar waveguides, coupling schemes to the outside world, evanescent-wave based detectors and the field of optofluidics. The perspectives and limitations of the different solutions are discussed in terms of analytical performance and fabrication costs. There has been an increased focus on cheap solutions in polymer materials that are amenable for mass production in order to ease commercialisation of the devices. This work will hopefully result in more commercial products that benefit from integrated optics, because the impact on commercial devices so far has been modest.

Special issue on optical micromanipulation

Few would have predicted the impact the laser has had across all of the natural sciences. Laser technology in tandem with microscopy has fuelled a revolutionary advance in biology and chemistry. Microscopic methods permit imaging of cells, nanoparticles, atoms and single molecules. Without doubt, biophotonics has emerged in many guises as a major player on the international arena, and has spawned an industry with an explosive growth rate. Notably, the influence of light is not restricted to passive imaging—it may also move, trap and manoeuvre objects from single atoms right through to the size of a large cell with no damage whatsoever. Given the well-known uses of high power lasers in surgery and industrial cutting, this sounds like science fiction, but at the size scale of these objects it is science fact: it is the area of optical micromanipulation that is the subject of this special issue. The field of optical micromanipulation has continued to impact right across the sciences in an unprecedented fashion, since its inception in the late 1960s. Excitingly the field has made an exceptional impact in single molecule biophysics and the physics of non-equilibrium systems largely due to the fact that an optical trap is an elegant and powerful force transducer. The field is also branching out into new directions: cell biology is benefiting from this advance. Trapping and microfluidics is an exciting combination within the broader remit of the field of optofluidics: methods of multiple traps using diffractive optics are permitting cell sorting, traps are aiding local viscosity measurements and novel biological studies are being performed. Combining traps with other spectroscopic methods and imaging modes is an interesting theme that poses interesting challenges but promises exciting new knowledge. All these areas are represented in this special issue, along with a number of contributions to quantitative modelling of optical fields suitable for trapping and of the motion of particles in these traps. The increasing sophistication and accuracy of these models allows for the optimization of the trapping process and shows how more and different information can be obtained. Light certainly has taken hold!