Building a setup capable of characterizing large and low-loss optics: “STAR”

We have built a setup called STAR that is capable of characterizing large and very low-loss optics. STAR stands for scattering, transmittance, absorption, and reflectance of the setup's measurement items using 1064 nm laser light, a wavelength in which we are currently interested. Thanks to the design concept in which most of the optical components are shared by each measurement, the system is reasonably compact and can be quickly switched from one measurement setting to another with only minor modification and without offloading the piece to be measured from the setup. The instrument is capable of scanning large areas of 500 mm diameter or larger and can be used for both coated and uncoated optics. It is described here in detail, and the results of some measurements are presented.