Advancements in GaN-based Horizontal-Cavity and Surface-Emitting Superluminescent Diodes for Next Generation Holographic Displays

Surface-emitting superluminescent diodes (SLDs) with horizontal cavities in the visible spectrum offer a significant advancement in optoelectronics, combining the benefits of LEDs and laser diodes. Characterized by broad emission spectrum, directionality, and high output power, SLDs are ideal for applications requiring high-brightness, high spatial coherence, and low temporal coherence, such as imaging and projection systems due to their speckle-free emission. This study focuses on SLDs emitting in the blue spectral region using gallium nitride (GaN) materials. Advanced fabrication techniques yielded a surface-emitting architecture using horizontal ridge waveguiding with a 45° total internal reflector on the facets, achieving high power and broad spectral output. The SLDs demonstrated a peak emission wavelength in the 4xx nm range with FWHM of 2-8 nm, depending on cavity length, and peak optical output power up to 1 W under pulse conditions. These features make SLDs cost-effective and suitable for next-gen optical systems, including holographic display applications, highlighting their potential for widespread adoption in high-performance technologies.