In 1871, fire swept through the burgeoning city of Chicago, destroying more than 17,000 buildings over three square miles. A building boom ensued, and thousands of new buildings were constructed in just a few years. It should come as no surprise that, with the smell of smoke still pungent around them, architects and builders looked to materials less flammable than wood.
Brick and stone were popular options. Such stout, load-bearing masonry used for exterior walls could support the weight of the building—to a point. As architects competed to build ever-taller buildings, base walls had to be made thicker to support the structure, which created the tapered appearance of many pre-20th- century buildings. But this building method had a significant limitation: After a certain height, it didn’t matter how thick the base of the supporting wall was built, the building would collapse under its own immense weight.
Architects did their best with this limitation, and, through design tweaks and iterations, they were able to build the north side of Chicago’s Monadnock building to a height of 16 stories. To this day, it remains the tallest load-bearing masonry building in the world. Under the laws of physics, it just wasn’t possible to go higher using load-bearing masonry.
The competition to build ever-taller buildings obviously didn’t end with the Monadnock building, as Chicago is now known as the birthplace of the skyscraper. In 1885, William LeBaron Jenney (who was notably trained as an engineer, not an architect) built the Home Insurance Building to a then-shocking height of 180 feet. He accomplished this architectural marvel by creating a frame of vertical and horizontal iron beams on which exterior masonry was hung. This construction approach significantly reduced the building’s weight without sacrificing strength. Though steel would quickly replace iron as the preferred scaffolding material, the modern skyscraper was officially born.
To realize this achievement, builders needed more than iterations on existing technology. They needed fundamentally new materials.
This issue of Photonics Focus looks at materials that are changing our understanding of photonics and causing step changes in knowledge and efficiency. For example, nanomaterials are increasing the efficiency of solar cells closer and closer to the theoretical limit. Topological materials, which have robustly stable surface states, have promising applications as catalysts, high-temperature superconductors, magnetic storage media, and even qubit generators for quantum computers. Meanwhile, AI is put to task to find new light-emitting molecules for OLEDs, which have yet to fully realize their promise of long life and cheap production.
SPIE is not a materials society, but materials are the bedrock of much of our science and engineering. While iterative improvements are important to advancing photonics, new materials have the potential to rocket us skyward.
Gwen Weerts, Photonics Focus Editor-in-chief
