Two-dimensional single-shot tomography using a virtually imaged phased array and a spatial phase modulator

Abstract

A virtually imaged phased array (VIPA) installed optical interferometer has been expanded to the two-dimensional (2D) tomography from the previous one-dimensional single-shot imaging technique with keeping the resolution and the measurement range. A single-shot measurement has been realized by a spatial phase modulator installed in the optical interferometer and tracing the delay time to pixel numbers on a 2D charge-coupled device (CCD) image sensor. The flexibility of the sample position was experimentally confirmed to be >25 mm, in relation to the VIPA coherency, for which the number of the interference order was confirmed to be 35. As a demonstration, a surface profile of stacked gauge blocks was observed. The repeatability of the surface position was 5 μm for the surface profilometry. In addition, a multilayer structure was observed using a glass plate. The experimental resolution was 53 μm when the amplified spontaneous emission light generated by the optical fiber amplifier was used for the light source. The single-shot measurement was confirmed by the 2D-CCD at a frame rate of 30 frames per second (FPS), and it provided evidence that the 2D scanless profilometry was successfully achieved using the VIPA optical device.