Stretchable, skin-conformal microscale surface-emitting lasers with dynamically tunable spectral and directional selectivity

Abstract

Coherent, monochromatic light sources that can intimately integrate with human body and yet offer state-of-the-art optoelectronic performance will create new opportunities in wearable and implantable electronics for a wide range of applications from personalized health monitoring, light therapy, to three-dimensional sensing and security. Here, we report stretchable, electrically driven surface-emitting microlasers capable of being conformally integrated on soft, curvilinear surfaces of biological tissues and providing wafer-level performance under mechanical and thermal environments relevant to skin physiology. GaAs-based microscale 850-nm vertical-cavity surface-emitting lasers derived from epitaxially grown source materials are integrated on a thin, elastomeric membrane in stretchable and thermally robust configurations enabled by printing-based heterogeneous material assemblies. The resulting stretchable, electrically pumped microlasers offer a stable continuous-wave operation under both uniaxial and biaxial tensile strains up to ∼120% in air as well as on the human skin, where the synergistic choices of mechanical strain and underlying heat-transfer medium provide versatile routes to dynamically control the spectral and directional characteristics of lasing.