REFLECTION MODE VOLUME HOLOGRAPHIC OPTICAL ELEMENTS (VHOES)

摘要

Reflection mode VHOEs are designed and fabricated for use in imaging and other applications that require high diffraction efficiency with minimal chromatic aberrations and astigmatism across the bandwidth. A single VHOE acts as a mirror to reflect light (0^th diffraction order) at the specified wavelength(s) and bandwidth with a principal ray at an angle equal to an angle of incidence of broadband light. A composite VHOE includes a complementary pair of input and output VHOEs each configured to diffract light into a non-zero N^th order. The input and output VHOEs are positioned in parallel to and offset from each other such that the filtered N^th order beam exits the composite lens on a path at the angle of incidence and parallel to the broadband light while suppressing the unwanted 0^th order beam. The composite lens improves suppression of unwanted wavelengths while still achieving minimal chromatic aberration.