Using vertical cavity surface emitting lasers as an alternative for transparent displays in augmented and mixed reality applications.
While virtual reality applications are gaining market traction, truly augmented and mixed reality applications based on transparent displays remain an ultimate end-goal for overlaying information without disconnecting the user from their surrounding environment. Although some products have been market tested, a number of key challenges remain. These include delivery of full-color images, energy consumption, and pixel size which detrimentally affects both image resolution and display transparency. Development of wearable augmented and mixed reality displays has solely leveraged either edge-emitting lasers or mini-LEDs however, both suffer from inherent limitations.
Researchers at the University of California, Santa Barbara have been investigating vertical cavity surface emitting lasers (VCSELs) as an alternative for transparent displays in augmented and mixed reality applications. VCSELs provide highly-directional emission in a compact form-factor – ≤100µm in diameter. The low threshold currents of VCSELs result in lower power consumption and increased battery lifetimes. Nonpolar and semipolar VCSELs have been shown to have a 100% polarization ratio, enabling true polarization-locked displays without requiring two separate inline polarizers and further increasing system efficiency. A fully transparent VCSEL would continue to improve the optical efficiency of displays while still providing the benefits of a traditional VCSEL in terms of packaging and polarization. In conjunction with transparent electrical traces, a transparent VCSEL would also open up the design window for see-through displays by removing restrictions on where the devices can be placed.