Nanophotonic Devices for Sensing and Imaging

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Introduction

Nanophotonics has left its mark and dumped other traditional methods or technologies in the trash in the evolving nanotechnology industry. These nanophotonic devices take advantage of altering the conductivity and transmission of light at the nanoparticle level to achieve increasing sensitivity, narrowing the aperture, and miniaturization. With the increased requirement of miniaturization, higher efficiency, and higher accuracy in sensing and imaging systems in defense, healthcare, the environment, and automotive applications, nanophotonic technology is opening the avenue for the next generation of optical systems. In this article, the author focuses on reviewing the recent advances in nanophotonic devices used for sensing and imaging and discusses how these technologies are revolutionizing optical devices.

The Rise of Nanophotonics in Sensing

The term ‘Nanophotonics’ means the manipulation of photons and other structures that are in a size range of hundreds of nanometers and where the rules of optics and quantum mechanics intermingle. This field has turned out to be very important for designing and fabricating new generations of sensors with improved performance parameters. In nanophotonic sensors, the capability of sensing at a more fundamental level is a large advantage given the inherent high sensitivity of the light-matter interactions at the nanoscale.

For instance, film nanostructures, including substrate-integrated hollow waveguides (iHWGs), employed in gas sensing have presented fabulous performance, especially at low concentration levels. These devices take the guidance of light through hollow waveguides embedded in a solid matrix; thus, they offer the advantages of being manageable in size and highly stable. The freedom of geometry design and the ability to engineer these waveguides to have variable optical characteristics make them well suited to a vast number of sensing applications, including industrial emissions, health care diagnostics, etc.

One more important innovation is the employment of graphene oxide (GO) coatings on microelectromechanical systems (MEMS)-based thermal emitters for gas sensing. In these devices, the radiative properties of the emitters are improved, thus allowing high selective gas detection at lower power consumption. The incorporation of nanostructured materials, such as GO, into conventional MEMS-based architectures emphasizes the usefulness of nanophotonic hybrid systems for updating existing sensing systems.

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Innovations in Imaging with Nanophotonics

Nanophotonics has been incorporated into the field of imaging systems, whereby smaller and more efficient devices are realized as well as greater efficiency with better image resolution than traditional optical systems. A perfect example of this innovation is metasurfaces, which are ultrathin, planar structures made of nanoscale elements that operate light, unlike optical systems.

Antenna metasurfaces are also employed in high-quality imaging systems, including metalenses, which are capable of delivering focused light. These metalenses are produced using the compatible Complementary Metal-Oxide-Semiconductor (CMOS) process, and therefore, they can be incorporated into contemporary technologies, such as popular portable devices such as smartphones and wearable gadgets. The capacity to fabricate metalenses then brings new opportunities in big imagery systems with minimal sacrifice in effectiveness.

Also, metasurfaces have been used in designing hyperspectral imaging systems. Such systems, where the spectral content at several different wavelengths can also be captured, find use in environmental culture, biomedical imaging, and material characterization. Metasurfaces applied to hyperspectral imaging systems make it possible to reduce the size of these devices and, in some cases, even increase the level of spectral resolution and sensitivity.

Compact nanophotonic systems for portable applications

continues to be an essential guide in the development of nanophotonic devices du0.e to the need to have portable or even wearable sensors or imagers. As a result, it has been possible to design most systems to have miniaturized and integrated circuits, with one device having numerous functions. For instance, on-chip NDIR CO2 sensors integrated with silicon photonics systems have been realized. Such sensors should be preferably compact so that they can be integrated into portable devices, but at the same time, they should enable measurements of CO2 levels with acceptable accuracy in real-time.

Another example of a compact nanophotonic device is the micro-electro-mechanical system (MEMS) mirror-integrated LiDAR system that is used in self-driving cars for sensing the environment and navigation. These LiDAR systems can use MEMS mirrors to rapidly and accurately steer the laser beam weight while still being energy efficient through the use of nanophotonic elements. This integration is crucial as far as putting into practice LiDAR in various uses, such as automobiles and drones.

The advances in compact sensing technologies are not limited to the exploration and establishment of microfiber-based sensing systems but also include the development of fiber-coupled substrate-integrated hollow waveguides (iHWGs). They offer possibilities of operation at a distance employing mid-infrared spectroscopy to sense gases and are versatile and highly sensitive analytic devices for environmental diagnostics. Given that these waveguides are compact and can be incorporated into other fiber-optic networks, more and more of them are being deployed in the field.

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The Role of Nanophotonics in Enhancing Sensor Performance

In addition, nanophotonic devices are compact and integrated and are reported to offer better performance as compared to optical sensors. One of the key functionalities that is implemented this way is optical frequency combs, which are light sources that emit a multitude of frequency lines equally spaced. However, these combs are useful in measurement systems that demand high spectral resolutions, such as in gas sensing and spectroscopy.

Integrated laser soliton microcombs, a subclass of optical frequency combs, have been developed for use in silicon photonics platforms to build miniature, high-precision sensors. These microcombs can cover many different frequencies and therefore can be used in many different types of sensing applications, from meteorological and geophysical to chemical and electromagnetic process control and measurement. These combs can also be incorporated into the silicon chips, making it possible to manufacture these sensors at a low cost.

For imaging, the integration of nanophotonic devices like metasurfaces and metalenses makes it possible to develop systems to produce images of higher resolution and better contrast. For instance, metasurfaces can readily define the phase, amplitude, and polarization of light and, therefore, offer the possibility of producing thin and lightweight lenses. These innovations are significant for application in biomedical imaging since a high degree of spatial resolution is crucial in the diagnosis and management of diseases.

Future Perspectives and Challenges

That said, the state of nanophotonic devices when it comes to sensing and imaging is very promising, but there is still a long way until these technologies hit the market. A primary objective is the ability to incorporate these devices into established systems, more so in environments requiring reliability and stability. Maintaining the stability of nanophotonic devices to be suitable for application in deplored conditions, for instance, in industrial uses of applications outdoors, will therefore play a crucial role.

The fifth problem is the lack of resolution on the material and process parameters of nanophotonic devices’ fabrication and testing. As some of these technologies transfer from the research laboratory to the manufacturing floor, it will be crucial for manufacturers to set standard operating procedures that would enhance the performance of the devices. This is not only the creation of nanostructures but also the inclusion of these structures with others like electronics or sensors.

Nevertheless, and despite these challenges, the future of nanophotonic devices for sensing and imaging is rather promising. Due to constant employment in their enhancement, these technologies may bring extensive change in healthcare, environmental examination, home electronics, and much more. With the ever-increasing requirement for wireless, compact, efficient, and precise sensing and imaging solutions, nanophotonics holds a rather prominent position in satisfying these requirements.

Conclusion

Nanophotonic devices are right on the cusp of the new generation of sensing and imaging devices. Nanoscale opto-electro-mechanical devices can be operated as efficient light modulators by the simple mechanism of manipulating light at the nanoscale level. From gas sensors that allow scientists to measure tiny amounts of pollutants to imaging techniques that are millions of times more powerful than stadia, nanophotonics is changing the way we can sense the physical world. This is an area that is still evolving, and as engineers and scientists seek for newer and better ways of harnessing nanotechnology, the prospects for the development of newer applications and improved innovations in the area of nanophotonic sensing and imaging appear almost endless.

References

  1. Wilk, A., Carter, J.C., Chrisp, M., Manuel, A.M., Mirkarimi, P., Alameda, J.B. and Mizaikoff, B., 2013. Substrate-integrated hollow waveguides: a new level of integration in mid-infrared gas sensing. Analytical chemistry, 85(23), pp.11205-11210.
  2. Li, N., Yuan, H., Xu, L., Tao, J., Ng, D.K.T., Lee, L.Y.T., Cheam, D.D., Zeng, Y., Qiang, B., Wang, Q. and Cai, H., 2019. Radiation enhancement by graphene oxide on microelectromechanical system emitters for highly selective gas sensing. Acs Sensors, 4(10), pp.2746-2753.
  3. Meng, C., Thrane, P.C., Ding, F., Gjessing, J., Thomaschewski, M., Wu, C., Dirdal, C. and Bozhevolnyi, S.I., 2021. Dynamic piezoelectric MEMS-based optical metasurfaces. Science Advances, 7(26), p.eabg5639.
  4. Li, N., Xu, Z., Dong, Y., Hu, T., Zhong, Q., Fu, Y.H., Zhu, S. and Singh, N., 2020. Large-area metasurface on CMOS-compatible fabrication platform: driving flat optics from lab to fab. Nanophotonics, 9(10), pp.3071-3087.
  5. Hu, T., Zhong, Q., Li, N., Dong, Y., Xu, Z., Fu, Y.H., Li, D., Bliznetsov, V., Zhou, Y., Lai, K.H. and Lin, Q., 2020. CMOS-compatible a-Si metalenses on a 12-inch glass wafer for fingerprint imaging. Nanophotonics, 9(4), pp.823-830.
  6. Wang, D., Watkins, C. and Xie, H., 2020. MEMS mirrors for LiDAR: A review. Micromachines, 11(5), p.456.
  7. Jia, X., Roels, J., Baets, R. and Roelkens, G., 2019. On-chip non-dispersive infrared CO2 sensor based on an integrating cylinder. Sensors, 19(19), p.4260.

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