Short-wave infrared digital holographic microscope: application to optical characterization of phase and amplitude of metasurface optics

In this work we describe the design, implementation and operation of a digital holographic microscope and apply it to quantitative phase measurements of precise optical components. This digital holographic microscope instrument operates in the short-wave infrared (1.550 μm), and has a spatial resolution of 4.2 μm with a field-of-view ∼ 500 μm2 . It is well suited for the characterization of diffraction-limited coronagraphic and phase-contrast focal plane masks which operate on the scale of the point spread function. Historically, these focal plane masks have been characterized indirectly, a process that involves integrating the individual components into larger optical systems and determining the system level performance. Thus, the direct measurement of the optical properties at these spatial scales enables their characterization before such integration into larger systems, thereby speeding both component and instrument development. Here we present the use of the digital holographic microscopy (DHM) that is tailored to the testing and characterization of these masks. We illustrate the operation of this new DHM instrument with data from two different metasurface devices - one scalar and one vector - to showcase the application and utility of the device.