The tailored spatial polarization of coherent light beams is important for applications ranging from microscopy to biophysics to quantum optics. Miniaturized light sources are needed for integrated, on-chip photonic devices with desired vector beams; however, this issue is unresolved because most lasers rely on bulky optical elements to achieve such polarization control. We developed quantum […]
Graphene exhibit unique electronic properties and mechanical flexibility that are beneficial for next-generation electronics. Crumpling graphene on elastomer sheets can engineer the properties depending on wavelength and orientation while maintaining structural integrity. However, tunability of nanotextures is limited because this process can only produce globally uniform features and graphene typically cracks in delaminated regions. By […]
Continuous-wave (CW) lasing at room temperature is critical for integration with opto-electronic devices and optimal modulation of optical interactions. Plasmonic nanocavities integrated with gain can generate coherent light at sub-wavelength scales, while insufficient gain with respect to losses and thermal instabilities in nanocavities has limited all nanoscale lasers to pulsed pump sources and/or low-temperature operation. […]
Selectively functionalized graphene can realize spatially defined properties that are highly desirable for atom-thin devices. We developed a scalable approach to realize area-specific properties in graphene using multiscale wrinkles. Patterned areas of graphene nanowrinkles and crumples followed by a single-process plasma reaction resulted in substrates with regions having different fluorination levels. Because the reduction in […]
Metalenses are compact lensing components based on rationally designed nanoscale building blocks. These planar devices are crucial for miniaturized imaging systems that can be integrated into portable electronic and optical devices. However, existing metalenses have fixed structures of hard materials that cannot be reshaped once fabricated and cannot adjust their focal spots adaptively based on […]
We achieved mechanical control of the lasing color by exploiting a lasing cavity based on periodic arrays of nanoparticles in a stretchable, polymer matrix. This materials system could achieve reversibly tunable lasing as well as superior sensitivity to applied strain. Large metal nanoparticles arranged in a lattice produce high-quality hybrid quadrupole plasmon modes that are […]
Understanding the underlying mechanism for the synthesis of metallic nanoparticles is crucial for strategic creation of desirable particles. We have recently designed a correlative approach to detect, visualize, and characterize intermediate species during a seedless, anisotropic nanoparticle synthesis. We showed how EPR radical signals of intermediates during a nanoparticle reaction can be combined with optical […]
Miniaturized lasers enable applications in on-chip optical communication, medical imaging, and nanoscale optical displays. Compared to traditional lasers, plasmonic nanolasers can break the diffraction limit and support ultrasmall mode volumes, but unwanted multi-modal nanolasing exhibits both uncontrolled mode spacing and output behavior. Single band-edge states can trap slow light and function as high-quality optical feedback […]
Plasmonic metasurfaces—structured materials with subwavelength units—are of interest for applications ranging from high resolution imaging to 3D holography. Integrated devices, however, are challenging to achieve because traditional plasmonic materials such as Ag or Au are not compatible with semiconductor processing. Recently, TiN has received attention as an unconventional plasmonic material because of its potential CMOS […]
Patterning three-dimensional (3D) structure into two-dimensional (2D) graphene is important for applications in flexible electrodes, stretchable electronics and energy storage devices. We have demonstrated a conformal wrinkling process that can generate hierarchical graphene architectures. Multi-scale graphene patterning is achieved by sandwiching a soft fluoropolymer skin layer between as-synthesized graphene and pre-strained polystyrene substrates. Because the […]