Development and Testing of a Dual-Wavelength Sensitive Photopolymer Layer for Applications in Stacking of HOE Lenses

Abstract

Diffractive optical elements (DOEs) have been in development for many years and are an exciting technology with the capability to re-direct light, using diffraction rather than refraction. Holographic Optical Elements (HOEs) are a subset of diffractive optical elements for which the photonic structure is created holographically, i.e., by recording a specific interference pattern in a suitable, photosensitive optical material. Volume HOEs are of particular interest for some applications because of their very high diffraction efficiency and single diffracted order; however, high dispersion and angular wavelength selectivity still present significant challenges. This paper explores a method for producing a compound DOE useful for situations where elements designed for two separate target wavelengths can be advantageously combined to achieve a highly efficient HOE with reduced dispersion. A photopolymer material consisting of two independently sensitized laminated layers is prepared and used in sequential holographic recording at two different wavelengths. The photonic structures recorded are investigated through examination of their diffraction peaks and comparison with the structure predicted by modeling. Finally, the device is illuminated with an expanded diverging beam at both target wavelengths and with white light, and a strong diffracted beam is observed.

Special Issue on Recent Advances and Future Trends in Nanophotonics

“…Volume HOEs show very high diffraction efficiency in single-order diffraction; however, angular wavelength selectivity and high dispersion still are considerable challenges. In order to achieve a highly efficient HOE with low dispersion, Keshri and co-workers [1] explored a fabrication method regarding a DOE with two separate target wavelengths. Two independently sensitized layers of photopolymer were stacked and used at two different wavelengths in sequential holographic recording.…”