Meta-optics and nano-optics are rapidly advancing, promising to revolutionize photonics systems and commercial applications, surpassing the limits of traditional optics. These materials, especially metasurfaces, are able to manipulate light in unique ways, leading to smaller, more versatile optical devices. Companies like Apple, Google, and Samsung are investing heavily in this field, aiming to integrate metaoptics into consumer electronics for improved imaging, authentication, and telecommunications.
The excitement around metaoptics stems from their potential to offer unprecedented control over light, enabling compact and versatile optical devices applicable across various sectors. Collaboration between physics, materials science, electrical engineering, and optics researchers is driving innovation in this area. Furthermore, the need to assess and validate the quality of metaoptics and metasurfaces presents opportunities for companies specializing in metrology.
While research groups have achieved significant progress and functional prototypes, the focus is shifting to mass production. Metaoptics, being compatible with CMOS fabrication techniques used for chip manufacturing through deep-ultraviolet lithography, are attracting major chip foundries. Companies like Metalenz, Moxtek, and NIL Technology are already producing metalenses with applications in polarization imaging, microscopy, and biosensing.
Researchers are actively developing innovative applications. For instance, polarization-sensitive cameras using metasurfaces, pioneered by Federico Capasso’s team at Harvard University, are being utilized in NASA projects and have led to Metalenz’s Polar ID for secure facial authentication. These cameras are more compact and efficient than traditional polarization cameras.
The unique properties of metaoptics, such as structural birefringence, are key to these advancements, allowing for polarization control without traditional birefringent materials. Semiconductor firms like STMicroelectronics are partnering with metaoptics companies for applications like facial recognition lidar in smartphones, and companies like Tunoptix are developing metalens designs for various camera applications.
Moxtek, a company with 25 years of experience in nano- and micro-optics, is mass-producing 1D periodic nanostructured metaoptic gratings using nanoimprint replication, highlighting the increasing manufacturability of these components. They are expanding production to meet the demand for emerging metaoptic designs.
Critical to the success of metaoptics is metrology, not only for final validation but throughout the design and manufacturing process. However, metrology for metaoptics presents challenges due to the nanoscale features. Traditional methods may not be sufficient to accurately assess these materials’ complex functionalities.
Metrology tool developers are responding to this need, creating tools specifically for metaoptics characterization. While research-grade tools are becoming available, enhancing test speed is crucial for high-volume production. Automated, in-situ, and real-time quality control is necessary to detect defects efficiently during mass production.
Key advancements in metrology include enhanced resolution, real-time in-situ monitoring suited for production environments, and scalability to handle large surface areas and volumes. Companies like Moxtek are upgrading to higher-volume measurement tools from TRIOPTICS.
Metaoptics are also contributing to advancements in metrology itself. Their unique characteristics require specialized metrology approaches, such as measuring focusing efficiency and higher-order focal spot information. Techniques using spectrally filtered light and scattering screens are being employed to characterize metalenses and other meta-elements.
Metasurfaces are also finding use in interferometry, where differences in diffraction patterns reveal phase changes induced by the metasurface. PHASICS Corp. offers interferometric systems designed for in-situ metaoptics measurements, suitable for use near manufacturing lines.
The increasing demand for compact and precise optical components is driving the integration of nanophotonics and metaoptics into industrial metrology. Polarization-based optical metrology could benefit from improved metasurface-based polarization components. Moreover, the semiconductor industry, already utilizing diffraction gratings for precise overlay metrology, is a natural fit for adopting metasurfaces as metrology targets due to material compatibility and potential for enhanced accuracy and smaller feature sizes.
Experts emphasize the need for greater industry awareness of the potential of metasurfaces and nanophotonics in advanced optical metrology. They also highlight the importance of national metrology institutes in supporting this development. Collaboration between academia and industry is crucial to tailor metasurfaces for specific metrology applications.
While challenges remain in scaling up production and adapting metrology techniques to industrial volumes, researchers believe that existing metrology methods can be enhanced to meet the needs of metaoptics characterization. Harnessing the unique capabilities of metasurfaces themselves can further improve metrology accuracy beyond traditional optics.