We have constructed a high-throughput spectrometer and a nonlinear optical tester used for the characterization of combinatorial thin-film libraries. The optical spectrometer consists of a multi-channel detector and an automated bidimensional translation stage. The transmission spectrum of an area of 0.5 mm x 2 mm can be measured for a wavelength range of 280-900 nm. Our nonlinear optical tester uses a compact mode-locked fiber-laser as an excitation source. The laser beam is focused by a graded index lens, the fundamental light is filtered out, and the third-harmonic (TH) light is detected by a photomultiplier. The data collection and the motion of the stepping motor-driven stage are synchronized. Typical measurement time for a composition-spread thin-film is 5 min. A demonstration is shown for a composition-spread thin-film of one-dimensional cuprate (SrxCa1-x)(2)CuO3 with gigantic third-order optical nonlinearity. (C) 2003 Elsevier B.V. All rights reserved.