Photonic Crystal Lasers

About

Summary: UCLA researchers in the Department of Electrical Engineering have developed a novel "bottom-up" fabrication method of forming high quality optical cavities for laser applications using only nanowires or nanopillars.    Background: Currently, optical microcavity fabrication methods using nanowires require multiple material depositions and additional fabrication steps including precision alignment of the randomly placed nanowires. Further, such microcavities are relatively inefficient at trapping light and consequently require a threshold power of a factor of 1000 or more. Although there are lasers such as the vertical cavity surface emitting lasers (VCSELs) and "top-down" photonic-crystal lasers with higher performance measures, they require the use of thick semiconductor films and thus cannot be incorporated onto integrated circuits without extensive and low yield process steps.    Innovation: Researchers at UCLA have developed a novel "bottom-up" fabrication method of producing high quality photonic crystal cavities by utilizing III-V nanopillars via a catalyst-free selective-area metal-organic chemical vapor deposition on masked GaAs substrates. The method of synthesis allows for precision lithographic control of nanopillar position and diameter enabling simultaneous formation of both the photonic band gap region and active gain region.   Applications: Laser applications  Optical communication in computer chips  Low cost photonic integrated circuits  Inexpensive and disposable light sources for spectroscopy in microfluidics    Advantages: Allows for wafer scale integration  Places cavities at predetermined locations  Simplifies the fabrication method and significantly reduces costs