Today, measuring optical flatness is a breeze—just fire up an interferometer, and you get instant, highly accurate results. But it wasn’t always this easy. Over the past 50 years, the field has gone from tedious manual fringe counting to cutting-edge AI-powered technology. While it’s great that modern tools handle the hard work, understanding how we got here is still important—especially when troubleshooting or dealing with older specifications.
From Fringe Counting to Laser Precision
Back in the day, measuring flatness meant manually inspecting interference fringes between glass surfaces—a process that required patience and a sharp eye. Then, in the 1970s and 1980s, laser-based interferometry changed the game, making measurements faster and more precise. By the 1990s, Phase-Shifting Interferometry (PSI) took it further by automating calculations, reducing human error, and improving accuracy.
Digital Revolution and AI Advancement
The 2000s and 2010s brought even more breakthroughs, like white-light and coherence-scanning interferometry, allowing for real-time 3D mapping. Now, AI-driven interferometers give near-instant results with angstrom-level precision, transforming industries like aerospace and semiconductors.
Why History Still Matters
With all these advancements, it’s easy to take modern technology for granted. But what happens when an interferometer spits out an unexpected result? Understanding the core physics behind the technology can make troubleshooting a whole lot easier. Plus, many industry specifications were written before today’s advanced tools existed. If you come across an unfamiliar measurement or spec, don’t hesitate to ask a vendor or expert for clarification—it’s better than guessing and hoping for the best.
Looking Ahead
Technology will keep evolving, but a solid grasp of the past helps drive future innovation. By understanding where optical flatness measurement started, today’s engineers can continue pushing the boundaries of precision optics.