Proton-implanted red photonic crystal VCSELs with high quality output beam

Abstract

We have fabricated proton-implanted photonic crystal (PhC) vertical-cavity surface-emitting lasers (VCSELs) emitting in the visible spectrum. The active region of the VCSELs is composed of multiple InGaAlP quantum wells resulting in an emission wavelength of 674 nm. A threshold current of 1.3 mA and single mode output power higher than 1 mW at room temperature have been achieved. The maximum continuous wave (CW) lasing temperature was found to be 55° C. The PhC VCSELs operate in a single fundamental mode with a side-mode suppression ratio (SMSR) larger than 30 dB and show a constant beam divergence of 8 degree (full angle) for all levels of injection current and various ambient temperatures. We compare ion-implanted and photonic crystal VCSELs and demonstrate that the controllable refractive index guidance effect of the PhC results in a stable beam output which makes these red VCSELs interesting for imaging applications.