نوافذ دائرية بجودة تجارية، سيليكا منصهرة منخفضة الهيدروكسيل بدرجة I2-IR

Ordered two of these for an interferometer setup and the surface quality is genuinely 60-40 or better, no sleeks or digs visible under my loupe. Diameter came in right at spec too, which matters when you're mounting them in a fixed ring.

I checked the parallelism on a bench and it came in well under 5 arc minutes, which is rare at this price. The 60-40 scratch-dig finish held up fine after a week of daily handling in our lab setup.

The 60-40 scratch-dig surface quality held up fine under a quick visual inspection, and the diameter tolerance was right on the money. Took a bit longer than expected to ship, but for the parallelism spec at under 5 minutes of arc, it's a solid deal for the price.