Planar Metalens: A Rising Star in the World of Optics

Imagine a bulky single-reflex camera becoming as light as a feather, thin as a sheet of paper. You might wonder: how is this possible?

 The answer lies in the metalens.

This isn’t just a futuristic fantasy; it’s a goal science is actively striving to achieve. Today, scientists are harnessing nano-optical structures to precisely control light, directing incoming rays exactly where they need to go. This revolutionary technology, known as the “metalens,” promises to completely transform traditional optics.

One could say that the metalens acts like a silent magician, using microscopic “magic antennas” to choreograph a new dance for light. Unlike conventional lenses, which rely on crude geometric shaping, the metalens resembles a delicate music box. Each tiny element functions like a piano key, accurately guiding light toward the direction we desire.

Now, extend this vision beyond cameras—to operating rooms, autonomous vehicles, and even rovers exploring Mars. Surgeons could perform more precise examinations with lighter endoscopes. Autonomous driving systems could more accurately identify obstacles ahead. Mars rovers could capture sharper images of celestial bodies using much lighter equipment.

What changes will this entirely new world, shaped by metalenses, bring?

1. Exploring Metalenses: A Decade of Refinement

Formally known as meta-lenses or planar hypersurface lenses, metalenses are two-dimensional (2D) flat lenses created using advanced optical principles and nanofabrication techniques. Compared to traditional lenses, metalenses employ a "metasurface" – an ultra-thin, planar, 2D metamaterial with sub-wavelength thickness. Its core mechanism involves manipulating the phase, amplitude, and polarization of light to achieve specific imaging or other optical effects.

The metasurface, the critical component of the metalens, is essentially a 2D plane composed of micro- and nano-structures. By precisely engineering these structures (such as their shape, orientation, height, etc.), scientists can exert highly specific control over various properties of incident light. This means that compared to complex multi-lens systems, a single, extremely thin metalens can perform sophisticated optical operations.

Research into planar metalenses began around a decade ago. Professor Federico Capasso’s team at Harvard University has been at the forefront since 2011, guiding both research directions and industrialization efforts. They published designs for metasurface lenses based on nanoscale unit cells in 2012 and, in 2016, presented a visible-spectrum metalens featured on the cover of Science.

Their design reportedly focuses light onto a spot approximately 400 nanometers (nm) in diameter. Crucially, instead of traditional curvature, Prof. Capasso’s team utilized a unique structure comprising multiple waveguides—tiny pillar-like features made of titanium dioxide (TiO₂), arranged in a specific pattern measuring about 600 nm long. These waveguides are termed “nano-fins.”

It took over ten years from concepts like phase gradients and generalized refraction/reflection models, through all-dielectric, high-transmission meta-lenses, to the realization of truly single-layer planar metalenses.

In summary, compared to traditional lenses, metalenses offer three primary advantages: thinness, low cost, and high efficiency.

• Size & Weight: While conventional lenses typically measure millimeters to decimeters thick, metalenses have thicknesses measured in hundreds of nanometers to micrometers—equivalent to roughly 1/50th the diameter of a human hair. Their compact size and lightweight nature provide unparalleled advantages for highly compact optical systems.
• Cost-Effectiveness: Manufacturing traditional lenses often involves complex grinding and polishing processes. Metalenses, however, can be mass-produced using semiconductor chip fabrication techniques, significantly reducing production costs. Mass-produced metalenses are estimated to cost only about 25% of their traditional counterparts.
• Flexibility & Integration: Due to their planar structure, metalenses integrate more easily with other electronic and optical components. This opens up new possibilities for various high-precision, miniaturized optical applications.

2. MR Glasses vs. Autonomous Driving: Who Will Be the First Adopter?

Today, metalenses demonstrate immense application potential across multiple fields, particularly in super-resolution microscopy, holography, and achromatic lens design. As a disruptive technology, metalenses not only stand to alter how we interact with the world but also have the potential to usher in a new era for the entire optical industry.

The VR/AR sector may be among the first impacted. Analyst Ming-Chi Kuo of TF International Securities tweeted in April this year stating that "the supply chain expects Apple to mass-produce its Metalens in 2024, likely replacing the plastic lens used for the iPad's Face ID transmitter." This implies Apple is developing metalens technology to replace plastic lenses within its devices, starting potentially with Face ID, moving to camera lenses, and ultimately AR glasses.

Although Apple's current Vision Pro uses primarily spatial computing technology (OST), its rumored AR glasses are widely considered one of the company's most promising and influential future products, representing a strategic move into the next decade.

However, creating market-ready AR glasses presents significant challenges. They must meet complex criteria including lightweight design, comfort, aesthetics, durability, safety, and intelligent interaction. Optical limitations are particularly pronounced.

Lenses are critical components in AR glasses, responsible for efficiently focusing displayed images onto the user's retina for a clear, realistic visual experience. Most current AR glasses rely on bulky, heavy curved lenses. These limit portability and can cause issues like color fringes, field distortions, and visual fatigue.

This explains Apple's investment in metalens technology. Besides solving optical bottlenecks for XR products, this tech could also address protruding lens issues in various consumer electronics like smartphones and cameras, enabling sleeker designs and improved optics.

The automotive sector, specifically autonomous driving, is also accelerating metalens R&D.

Reports indicate that both LG and Samsung are developing metalenses intended for ultra-thin automotive cameras used in self-driving vehicles.

LG Innotek, LG Group's camera development subsidiary, states it is developing a metalens just 1/10,000th the thickness of conventional glass or plastic lenses. Kang Min-seok, CTO of LG Innotek, commented: "We aim to replace refractive lenses with meta-lenses to create ultra-thin cameras. Automobiles are our primary initial target application, followed by various mobile products and cameras."

Similarly, in 2021, Samsung confirmed at the same forum that it was researching metalenses and preparing for their commercialization.

While large-scale mass production of metalenses is still in its early exploration phase transitioning from lab to factory, early-stage startups have already begun strategically investing in this technology.

• June 2022: Tianjin Shanghe Photonics Technology Co., Ltd. (specializing in metasurface photonic chips), completed a pre-A financing round worth several million RMB, jointly led by Shunyu Industrial Fund and Jingwei Capital, with existing investor Zhongke Innovation Star participating.
• April 2023: Imagia (focused on silicon-based optical metalenses for AR glasses) announced $4.5 million in funding led by Gates Frontier, with participation from MetaVC Partners and others.
• October 2022: Metalenz (founded in 2017 and spun out from Prof. Capasso's group at Harvard) secured $30 million in Series B funding led by Neotribe Ventures. Currently the fastest progressing towards commercialization. In June 2023, United Microelectronics Corporation (UMC) announced it had begun manufacturing Metalenz metasurfaces at its 12-inch wafer fab in Singapore, with initial OEM commercial end-products shipping starting Q3 2023.
  (Source: Compiled by YZSY Optics based on public information)

3. YZSY Optics Perspective: Bullish on Early Adoption in Consumer Electronics

Metalens technology offers significant advantages in terms of lightness, cost-effectiveness, and efficiency, theoretically capable of replacing the vast majority of existing optical lens systems.

However, due to current manufacturing limitations and fundamental theoretical gaps in addressing chromatic aberration for visible light and higher frequencies, metalens applications remain largely confined to the infrared spectrum—such as in spectrometers and Time-of-Flight (ToF) modules.

From YZSY Optics' perspective, widespread adoption in consumer electronics is expected within the next 2-3 years. Large manufacturers scaling up production will stabilize processes and make costs predictable. Furthermore, opportunities exist to develop innovative features leveraging metalenses, such as extracting polarization information usable for identifying target material properties. Future applications could include precision obstacle avoidance in devices like robotic vacuum cleaners.