Aberration reduction and unique light focusing in a photonic crystal negative refractive lens

Optical vacuum cleaner by optomechanical manipulation of nanoparticles using nanostructured mesoscale dielectric cuboid

Here, we propose the concept of an "optical vacuum cleaner" for optomechanical manipulation of nanoparticles. We utilize a dielectric cuboid to generate an optical gradient force exerted on the nanoparticles for particle's hovering and trapping. We show that the permittivity contrast between the particle and the nanohole leads to the deep subwavelength light confinement and enhancement at the opening of the nanohole located at the shadow surface of the particle. The proposed "optical vacuum cleaner" can be utilized in optomechanical manipulations on particles such as noble metal nanoparticles adsorbed on surfaces or controlling the particles taking part in cellular uptake.

Anomalous refractive effects in honeycomb lattice photonic crystals formed by holographic lithography

We have investigated for the first time the anomalous refractive effects of a photonic crystal (PhC) formed by holographic lithography (HL) with triangular rods arranged in a honeycomb lattice in air. Possibilities of left-handed negative refraction and superlens are discussed for the case of TM2 band with the index contrast n = 3.4:1. In contrast to the conventional honeycomb PhC made of regular rods in air, the HL PhCs show left-handed negative refraction over a wider and higher frequency range with high transmissivity (>90%), and the effective indices quite close to -1 for a wide range of incident angles with a larger all-angle left-handed negative refraction (AALNR) frequency range (Deltaomega/omega approximately 14.8%). Calculations and FDTD simulations demonstrate the high-performance negative refraction properties can happen in the holographic structures for a wide filling ratio and can be modulated by changing the filling ratio easily.

Focusing light in a curved-space

We use transformation optics to demonstrate 2D silicon nanolenses, with wavelength-independent focal point. The lenses are designed and fabricated with dimensions ranging from 5.0 microm x 5.0 microm to 20 microm x 20 microm. According to numerical simulations the lenses are expected to focus light over a broad wavelength range, from 1.30 mum to 1.60 mum. Experimental results are presented from 1.52 microm to 1.61 microm.

Photonic crystal lens for coupling two waveguides

We report the design, fabrication, and characterization of a new nanophotonic device comprising a two-dimensional photonic crystal (PhC) lens of size 3x4 microm fabricated in silicon-on-insulator. The PhC lens is put at the output of a planar waveguide of width 4.5 microm to couple light into a planar waveguide of width 1 microm, with two waveguides being of length 5 mm. A 1 microm off-axis displacement of the smaller waveguide leads to an 8-fold reduction of output light intensity, which means that the focal spot size at output of the PhC lens in silicon is less than 1 microm. The simulation has shown that the PhC lens has maximal transmittance at 1.55 microm, with the coupling efficiency being 73%. The focal spot size of the lens in air calculated at the FWHM is 0.32lambda (where lambda is the wavelength).