High efficiency reflective waveplates in the midwave infrared.

We demonstrate a high efficiency reflective waveplate which exhibits incidence angle dependent phase shift tuning capabilities in the midwave infrared. Using Finite Difference Time Domain (FDTD) modeling, the phase shift and reflection efficiency are simulated for a variety of geometrical parameters, the results of which are then employed to optimize design. Devices were fabricated and both the polarization and efficiency characteristics were measured and compared to FDTD simulations showing excellent agreement. Further, the potential for scalability to other wavelength ranges and the capability to generate an arbitrary phase shift are explored to demonstrate the versatility of our design.