Ultrasphere™ Transmission Spheres

Ultrasphere™ Transmission Spheres
Zygo's Ultrasphere™ transmission spheres are designed to enable surface form metrology with an uncertainty in the RMS* of ≤ 3.2 nm (λ/200 at 633 nm) when used with a ZYGO interferometer, and are best suited for metrology of test optics with ≤ 40% reflectivity.

They include 4-inch (101.6-mm) diameter transmission spheres with f/numbers of f/0.75, f/1.5 and f/3.3, with λ/40 PVr (λ = 633 nm) surface form. Other 4- and 6-inch Ultrasphere transmission spheres are available.

Each Ultrasphere transmission sphere includes absolute calibration of the reference surface, and are shipped with the resulting MetroPro *.dat file and 37-term Zernike fit on a USB memory stick.

Download the spec sheet for additional details.

* Assumes form metrology of smooth spherical surfaces, a well-nulled cavity, data averaging to minimize systematic noise, a suitably stable environment, and uncertainty estimation following ISO's "Guide to the Expression of Uncertainty in Measurement" (1995) with k=1.

PVr is defined as the 36 term Zernike fit plus 3 times the rms residual of the Zernike fit.