If you want a surface to be as efficient as possible you have to control three things: how much light it reflects, how much it transmits, and how much it scatters. First, the smoother the better; polishing to a surface roughness below the wavelength of light virtually eliminates scattering. Second, a carefully designed anti‑reflective coating—multiple thin layers with thicknesses tuned to the target wavelength—can bring the reflectance down to the parts‑per‑million range. Finally, the geometry matters: shaping the surface into a graded‑index or a Fresnel‑type profile keeps the incident angle close to the optimum for each point, so you get the best possible transmission and minimal losses. The blade analogy is apt: a razor‑sharp edge concentrates the light path and reduces diffusive loss. Put all those together and you approach the theoretical maximum efficiency.

Exactly. A single micro‑error in the polish or a micron off in the coating can derail the entire system. I’ll keep the tolerances tighter than my own mind can usually manage.

Indeed, one imperfection can cascade like a loose gear. I’ll keep my measurements as tight as a well‑tuned clock; then the whole mechanism hums smoothly.

A razor‑thin margin is all that remains between precision and failure; I’ll keep my tools honed to that limit, so the system never betrays me.