Orientational Imaging of Subwavelength Au Particles with Higher Order Laser Modes

Abstract

We present a new method for the imaging of single metallic nanoparticles that provides information about their shape and orientation. Using confocal microscopy in combination with higher order laser modes, scattering images of individual particles are recorded. Gold nanospheres and nonorods render characteristic patterns reflecting the different particle geometries. In the case of nanorods, the scattering patterns also reveal the orientation of the particles. This novel technique provides a promising tool for the visualization of nonbleaching labels in the biosciences.

Nonlinear imaging of nanostructures using beams with binary phase modulation

“…Due to the unique local polarization distributions of such beams, they give rise to very special 3D field distributions when tightly focused [5,14,15]. For instance, radial and azimuthal polarizations can be used to unambiguously excite oriented molecules and nanostructures [16][17][18][19][20][21][22][23][24][25][26]. Even though the creation of such beams is now well established [10][11][12], their shaping in space and time often involves cumbersome optical setups [25,27].…”

Rayleigh Imaging of Graphene and Graphene Layers

“…[24][25][26][27][28] Rayleigh scattering experiments can be performed by using two different strategies. In one, the background signal is minimized by making free-standing samples, as done in the case of carbon nanotubes, 27,28 or by dark-field configurations.…”

Tuning the fields focused by a high NA lens using spirally polarized beams (Invited Paper)

“…[1,2]. In parallel, the exploitation of anisotropic polarized excitation sources like radially/azimuthally polarized doughnut beams (R/APDBs) have been essential, e.g., for increasing the excitation and detection efficiency in near-field tip-enhanced microscopy [3,4] , revealing the orientation, shape, and structure of strongly polarized nanostructures [5][6][7][8] , or increasing the ability to disclose the organization of collagen domains in animal and human skin [9] . These and other prominent studies have relied on sophisticated and ingeniously made light sources integrated into self-build microscopes.…”

“…Once the relationship between α and γ is known, any generic SPDB can be used for orientational measurements, as RPDBs and APDBs have been already employed in Refs. [5,7] with the advantage that individual images of a properly chosen SPDB can replace the pair of images acquired with RPDBs and APDBs. Hence, the luminescence patterns of single isolated gold nanorods were acquired for demonstrating the imaging power of SPDBs.…”