Reference Sphere 37mm 40%

The f/0.68 aperture gathers light beautifully for my interferometry setup, and the 1/20 wave figure is exactly what I needed for calibration work. It's a precision piece that feels solid in the mount, and it's been consistent across multiple tests.

The 40% reflectivity is spot-on for my interferometry setup, and the 1/20 wave surface accuracy gives me confidence in my measurements. It paired perfectly with my existing ZYGO gear without any fuss. Exactly what I needed.

The f/0.68 aperture on this 37mm sphere makes alignment work noticeably quicker than with slower references. It holds a crisp 1/20 wave figure, and the 40% reflectivity balances return signal strength nicely without needing a filter wheel.