II–VI compound semiconductor quantum-well heterostructures were fabricated for use as efficient, narrow-spectrum, photoluminescent color converters to generate green, yellow, or red light when photopumped with blue GaInN light emitting diodes (LEDs). This approach promises high efficiencies in a wide range of wavelengths that includes the green-yellow portion of the spectrum where conventional LEDs offer relatively low efficiency. External quantum conversion efficiencies of 60%–70% and output spectra with full width at half maximum of 15 nm were achieved using CdZnSe–CdMgZnSe quantum wells grown by molecular beam epitaxy on InP substrates.
Polarized catadioptrics (i.e., folded optics, pancake lenses) offer increased resolution and reduced aberrations across a wider field‐of‐view, and in a smaller physical package than conventional refractive optics for virtual reality (VR) head‐mounted display applications. One of the major challenges with polarized catadioptrics is achieving a high contrast ratio. In this paper we will review data generated experimentally and through simulations that demonstrate the impact of key system attributes on contrast ratio. The parameters we explore include the quarter‐wave plate material selection, scattering in the optical components, and rotational alignment between the polarization sensitive components.
Polarized catadioptric optics systems are an emerging solution for virtual reality (VR) head mounted displays (HMD). A good VR optical system should have a large pupil volume to tolerate multiple interpupillary distances and to accommodate eye rotation as the user scans across the field of view (FOV). In this paper we review the 3M™ High Acuity Reflective Polarizer (HARP) optical lens and module. We present empirical and modeling data for lens module performance including MTF as functions of pupil rotation, decenter, and diopter adjustment range. The large eye box and decentering tolerance yields a natural viewing experience. 3M™ HARP optics demonstrates the promise of pancake optic designs to deliver realistic immersive VR experience.
Energy-momentum (dispersion) relations are a foundational framework for photonic device design, but our incomplete command thereof still limits key technologies. For instance, narrowband optical combiners for augmented reality should ideally reflect with unitary efficiency selected wavelengths that encode the artificial information over a large range of oblique incident angles, yet they are conventionally severely limited in field of view by dispersion. Here, we engineer nonlocal metasurfaces to support quasi-bound states in continuum with zero first-order resonant frequency dispersion at any desired quasi-momentum by exploiting a zone-folding technique that leverages a change in the lattice family. Our platform thereby advances photonic devices by enabling unprecedented control over the energy-momentum properties of nonlocal states, rationally controlled through a perturbation scheme that produces minimal distortion to non-resonant light.
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