We demonstrate a novel class of elements called Far-Field Geometric Phase Holograms (FGPH) capable of producing far-field output images free of chromatic distortion for a broad range of input wavelengths. The FGPH utilizes the geometric phase which applies the same phase profile to any incident wave regardless of wavelength. Thus, the fidelity of an image produced by an FGPH is the same for all wavelengths. However, being a diffractive element, the FGPH is still dispersive in that the size of a generated image depends on the replay wavelength according to the diffraction equation. In this paper, we give theory for the ideal FGPH element, describing its replay characteristics and unique polarization properties. We experimentally realize an FGPH element using photo-aligned liquid crystals patterned with a direct-write system. We characterize the fabricated element and show the theory to be valid. Generally, this new class of polarization sensitive elements can produce broadband undistorted images with high diffraction efficiency.

Date Published: 10 March 2015
PDF: 6 pages
Proc. SPIE 9386, Practical Holography XXIX: Materials and Applications, 938609 (10 March 2015); doi: 10.1117/12.2084722

Published in SPIE Proceedings Vol. 9386:
Practical Holography XXIX: Materials and Applications
Hans I. Bjelkhagen; V. Michael Bove Jr., Editor(s)