Geometric phase lens (“GPL”) technology and color selective filters (“CSFs”), when combined together, provide a ground breaking, broadband, thin film lens capability. While a GPL enables highly customizable, spherical-aberration-free lens functionality in a thin film, until now GPLs have a different focal length for all wavelengths of light (see Figure 1). This is a limiting factor for certain broadband applications. Adding color selective filters to GPLs allows the focal length of each band of color to be separately determined, enabling the focal length of a broadband of wavelengths to be substantially the same (see Figure 1).
While there are many combinations of GPLs and color selective films that result in similar broadband functionality, the preferred solution for correcting three colors (red, green, blue) consists of three GPLs and two CSFs, for example (see Figure 2).
Our initial development has virtually eliminated color separation (see Figure 3) in imagining systems in many applications, while maintaining all the design, performance and thinness advantages of GPLs. It’s a truly groundbreaking advancement of the GPL technology, that will be available for early prototype and partnership development in the next few months.
GPL Basics: A Geometric Phase Lens, or GPL, is an innovative new flat optic that functions like a lens. A GPL features a spatially varying geometric phase that produces only three possible waves (e.g., from optical axis orientation map). (1) The Primary Wave, with wavefront phase, (2) the Conjugate Wave and (3) the Leakage Wave (0-order), with wavefront phase unchanged. The Phase is completely continuous and unbounded, all three output waves can be from 0% to 100% and the spectral behavior depends on the retardation not the spatial phase profile.
The basic function of a GPL is a nonlinear orientation angle where the function phase is as follows:
The phase can be aspheric, aberration corrected, or any function and the input polarization selects the ± sign of the focal length. The characteristics of GPLs combine a very unique set of design freedoms and functionality that make GPLs ideal for many applications.
CSF Basics: While there are different technologies that offer a color selective filter function, ColorSelect® filters from ColorLink Japan, Ltd offer industry leading efficiency in rotation of the state of polarization of a primary color band by 90 degrees while the complementary color band retains the input state of polarization. This allows color splitting and color combining together with GPLs. Custom filters can be designed to rotate any desired spectrum band.
For information on GPLs and to learn more about early access to GPL+CS when they become available, contact ImagineOptix via our website at www.imagineoptix.com
For information about commercially available ColorSelect® filters from ColorLink Japan, Ltd, visit their website at www.colorlink.co.jp