High atop a mountain in Chile's arid Atacama Desert, the European Space Observatory (ESO) is on the brink of completing a groundbreaking project: the world's largest optical telescope, aptly named the Extremely Large Telescope (ELT). Set to begin capturing images in 2028, the ELT is expected to significantly advance our understanding of the universe. At the heart of this technological marvel are some of the most sophisticated mirrors ever constructed.
 |
| The extraordinary mirrors behind groundbreaking technologies |
Dr. Elise Vernet, an adaptive optics specialist at ESO, has been overseeing the development of five massive mirrors that are key to the telescope’s functionality. Each mirror is a masterpiece of optical engineering, essential for gathering and channeling light to the telescope’s instruments.
Among these, the M2 mirror—a 14-foot (4.25-meter) convex surface—is described by Dr. Vernet as "a piece of art." However, the true marvels of precision and design are the M1 and M4 mirrors.
The primary mirror, M1, is the largest ever created for an optical telescope. Spanning an extraordinary 39 meters (128 feet) in diameter and comprising 798 hexagonal segments, M1 is engineered to function as a single, flawless mirror. It is designed to collect 100 million times more light than the human eye, maintaining its position and shape with a precision 10,000 times finer than a human hair.
Equally impressive is the M4 mirror, the largest deformable mirror ever made. This mirror can alter its shape 1,000 times per second to correct for atmospheric turbulence and the telescope’s vibrations, ensuring crystal-clear imagery. The M4’s surface, made from a glass-ceramic material, is astonishingly thin—less than 2 millimeters (0.075 inches)—and is composed of six flexible petals. These were meticulously crafted by Schott in Mainz, Germany, and later polished and assembled by Safran Reosc near Paris.
As these mirrors near completion, they will soon be transported to Chile for installation, marking a significant milestone in the ELT project. But while these mirrors are set to explore the vastness of space, equally impressive advances in mirror technology are happening on a much smaller scale.
At the Max Planck Institute for Quantum Optics in Garching, Germany, researchers have developed a quantum mirror that operates at the atomic level. In 2020, a team successfully created a mirror by aligning a single layer of 200 atoms to collectively reflect light—a mirror so small it is invisible to the naked eye. By 2023, they advanced this technology by positioning a single, controlled atom at the center of the array, creating a "quantum switch" that can toggle the atoms between transparent and reflective states. Dr. Pascal Weckesser, a postdoctoral researcher at the institute, explains that this breakthrough could lead to future applications in quantum technologies, such as hack-proof communication networks.
Further north, in Oberkochen, Germany, the optics company Zeiss has been developing ultra-flat mirrors for extreme ultraviolet lithography (EUV) machines, which are crucial in manufacturing computer chips. These mirrors, used by Dutch company ASML, are so flat that if scaled to the size of Germany, the highest peak would be just 0.1 millimeters tall. This level of precision allows for the production of chips with increasingly dense transistor arrays, pushing the limits of what is possible in microchip technology.
Zeiss’s advancements are paving the way for even more powerful computer chips. By 2030, the goal is to produce microchips with one trillion transistors—a significant leap from today’s hundred billion. Dr. Frank Rohmund, president of semiconductor manufacturing optics at Zeiss, notes that this progress is vital for developing future technologies, including artificial intelligence, which were unimaginable just a decade ago.
As we look to the future, mirrors—whether they are exploring the cosmos or enabling the next generation of quantum and computing technologies—will play a central role in shaping what humanity can achieve. The next decade promises to be one of extraordinary discovery and innovation, with these advanced mirrors leading the way.
0 Comments