Broadband Wide-Angle Metalens with Uniform Near-Infrared Illumination
Pekman, Asli (2024)
2024
Master's Programme in Photonics Technologies
Tekniikan ja luonnontieteiden tiedekunta - Faculty of Engineering and Natural Sciences
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Hyväksymispäivämäärä
2024-11-20
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-202411069970
https://urn.fi/URN:NBN:fi:tuni-202411069970
Tiivistelmä
In imaging technology, infrared illumination plays an important role in both front-facing and world-facing cameras. These cameras are integrated into various devices such as smartphones, tablets, laptops, wearables, and automotive systems. While Front-Facing infrared illumination is used for face authentication, eye tracking, and driver monitoring, World-Facing infrared illumination is used for 3D sensing, time-of-flight sensors, and lidars.
When designing optical systems for infrared illumination, several key objectives come into play: uniformity, beam flexibility, low power consumption, and compact design. Achieving uniform beam distribution across the field of illumination is critical. Uniformity enhances the signal-to-noise ratio (SNR) of the optical systems, leading to better performance. The optical system should allow flexibility in adjusting the beam deflection angle and the field of illumination (FoI). This adaptability ensures optimal performance across different scenarios. Minimizing power usage is essential for consumer electronics, and efficient beam designs contribute to overall energy savings.
Metasurfaces, composed of subwavelength structures, provide the required flexibility while maintaining a thin profile. These engineered surfaces manipulate light at the nanoscale, allowing precise control over beam properties.
In this thesis, the central wavelength has been chosen in the Short-Wave Infrared (SWIR) part of the infrared spectrum, resulting in images that exhibit higher resolution, less noise, better contrast, and improved eye safety.
When designing optical systems for infrared illumination, several key objectives come into play: uniformity, beam flexibility, low power consumption, and compact design. Achieving uniform beam distribution across the field of illumination is critical. Uniformity enhances the signal-to-noise ratio (SNR) of the optical systems, leading to better performance. The optical system should allow flexibility in adjusting the beam deflection angle and the field of illumination (FoI). This adaptability ensures optimal performance across different scenarios. Minimizing power usage is essential for consumer electronics, and efficient beam designs contribute to overall energy savings.
Metasurfaces, composed of subwavelength structures, provide the required flexibility while maintaining a thin profile. These engineered surfaces manipulate light at the nanoscale, allowing precise control over beam properties.
In this thesis, the central wavelength has been chosen in the Short-Wave Infrared (SWIR) part of the infrared spectrum, resulting in images that exhibit higher resolution, less noise, better contrast, and improved eye safety.