META ROSETTA
What is Metadevice?
Metadevices are an emerging type of artificial optical component, typically composed of millions of unit structures (also known as nano-antennas). The dimensions of these unit structures are usually at the subwavelength scale, meaning their size is smaller than half the wavelength of the operating light. By precisely arranging these unit structures, valuable metadevices can be created, such as metalenses, antenna systems, sensors, and fiber-optic endoscopes.
Metalens v.s Conventional lens
Meta-lenses use semiconductor processes, enabling large-scale and rapid production of high-precision lenses. Unlike traditional lenses that require multiple elements to correct spherical and chromatic aberrations, a single meta-lens can achieve this, making the lens module more compact and lightweight.
Thermal Metalens
Thermal Conventional lens
Light and Slim
Thick and Heavy
Size
Abberation
No
Yes
Opitcal
Efficiency
Good
Best
Cost
Low
High
Process
Semiconductor
Grinding
Semiconductor Manufacturing Technique
The manufacturing of traditional lenses primarily relies on grinding and plastic injection techniques. For thermal imaging, traditional lenses are typically made from silicon and germanium, and grinding is the only processing method. Due to the high difficulty of this method, it is challenging for Taiwanese manufacturers to produce them independently. In contrast, the production process of thermal imaging meta-lenses uses semiconductor processes, as shown in the figure below, mainly including photolithography and dry etching. The photo shown in the figure is a meta-lens independently developed by our team. With the excellent foundry capabilities of semiconductor manufacturers, meta-lenses can achieve mass production and reduce production costs. The precision of semiconductor processes reaches the nanometer level, providing high-precision meta-lenses.
Dispersion
Metalenses achieve effective dispersion elimination through a single lens structure composed of numerous resonant units, which cleverly adjust the refractive index. These lenses use special materials or structures to ensure that different wavelengths of light experience similar refractive indices within the lens, thereby greatly reducing dispersion effects. Additionally, the aspherical shape of the meta-lens adopts a non-traditional design, helping to achieve uniform focal lengths for various wavelengths of light, further minimizing the impact of dispersion. Optical anisotropy is also carefully applied, utilizing variations in refractive index in different directions to achieve a more uniform focal point across different wavelengths.
Spherical Abberation
The structure is meticulously composed of numerous resonant units, which are optimized during the design phase to achieve the spherical and chromatic aberration correction effects of meta-lenses. The image below shows the focal spot size of our developed meta-lenses capable of eliminating aberrations. Measurement results indicate that these meta-lenses, which can eliminate aberrations, have a focal spot size close to the theoretical diffraction limit, providing superior imaging quality.
D/MOE (Face ID)
DOE (Diffractive Optical Elements) use microstructures to alter the phase or shape of light, achieving various optical functions, including beam shaping, wavefront modulation, and multi-wavelength operation. They are widely used in laser technology, interferometric instruments, and communications.
In contrast, MOE (Meta-Optic Element) can solve the issue of reduced diffraction efficiency in traditional dot projectors caused by the aging of collimating lenses.
