We show how to design an optical device that can perform any linear function or coupling between inputs and outputs. This design method is progressive, requiring no global optimization. We also show how the device can configure itself progressively, avoiding design calculations and allowing the device to stabilize itself against drifts in component properties and to continually adjust itself to changing conditions. This self-configuration operates by training with the desired pairs of orthogonal input and output functions, using sets of detectors and local feedback loops to set individual optical elements within the device, with no global feedback or multiparameter optimization required. Simple mappings, such as spatial mode conversions and polarization control, can be implemented using standard planar integrated optics. In the spirit of a universal machine, we show that other linear operations, including frequency and time mappings, as well as nonreciprocal operation, are possible in principle, even if very challenging in practice, thus proving there is at least one constructive design for any conceivable linear optical component; such a universal device can also be self-configuring. This approach is general for linear waves, and could be applied to microwaves, acoustics, and quantum mechanical superpositions.

High-order sideband nonlinear optical properties in a DNA–quantum dot coupled system are investigated theoretically here. In this paper, we demonstrate the significant enhancement of the third- and fifth-order optical nonlinear properties of the system by applying the pump-probe technique with pump-exciton detuning tuned to zero. It is shown clearly that these phenomena cannot occur without the DNA–quantum dot coupling, implying some potential applications like DNA detection. We can also obtain and tune the significantly amplified sideband beams at frequencies ωp
2ωD. This research could provide people a deeper insight into the nonlinear optical behaviors in coupled DNA–quantum dot systems.

The concept of using plasmonic nanostructures to manage light in solar cells has offered an unprecedented potential for dramatically increased solar energy conversion efficiency that breaks the previously predicated efficiency limit. In the past decade, intensive research efforts have been focused on this field. However, nanoplasmonic solar cells still remained in the laboratory level. To facilitate the transformation of the nanoplasmonic solar cell concept to a viable high-efficiency technology solution for the solar industry, it is essential to address key fundamental as well as practical challenges including the detrimental absorption of metallic nanostructures, narrow-band absorption enhancement in the active layer, the high cost and scarcity of noble metals, and the expensive and complicated plasmonic nanomaterial fabrication and integration methods. In this paper, after a brief review of our main results in nanoplasmonic solar cells, we present our strategies for using innovative photonic methods to overcome these challenges and demonstrate a large-area (173 cm2) broadband plasmonic thin-film solar minimodule with an efficiency of 9.5% resulting from the enhanced plasmonic light scattering enabled by silver lumpy nanoparticles with an ultralow nanoparticle coverage density of 5%.

Gold nanorods (GNRs) have potential applications ranging from biomedical sciences and emerging nanophotonics. In this paper, we will review some of our recent studies on both microscopic and macroscopic manipulation of GNRs. Unique properties of GNR nanoparticles, such as efficient surface plasmon amplifications effects, are introduced. The stable trapping, transferring, positioning and patterning of GNRs with nonintrusive optical tweezers will be shown. Vector beams are further employed to improve the trapping performance. On the other hand, alignment of GNRs and their hybrid nanostructures will be described by using a film stretch method, which induces the anisotropic and enhanced absorptive nonlinearities from aligned GNRs. Realization and engineering of polarized emission from aligned hybrid GNRs will be further demonstrated, with relative excitation–emission efficiency significantly enhanced. Our works presented in this review show that optical tweezers possess great potential in microscopic manipulation of metal nanoparticles and macroscopic alignment of anisotropic nanoparticles could help the macroscopic samples to flexibly represent the plasmonic properties of single nanoparticles for fast, cheap, and high-yield applications.

We show that superoscillating light fields, created using the method of optical eigenmodes, enable more efficient multiphoton-mediated cell transfection. Chinese hamster ovary cells are transfected with a plasmid and exhibit expression of DsRed-Mito in the mitochondria. We demonstrate an efficiency improvement of 35% compared to the diffraction-limited spot.

We analyze the properties of a dual-beamtrap of orthogonally intersecting beams in the geometrical optics regime. We derive analytical expressions for the trapping location and stability criteria for trapping a microparticle with uncollimated Gaussian beams. An upper limit for the beam waist is found. Optical forces and particle trajectories are calculated numerically for the realistic case of a microparticle in intersecting liquid-core waveguides.

We briefly review the development of gain-switched rare-earth-doped fiber lasers and their applications in wavelength conversion to mid-IR, supercontinuum generation, and medicine in recent years. We illustrate the similarities between gain-switching and Q-switching techniques that will provide tools for the design and optimization of the gain-switched fiber lasers. From the nature of the gain-switched fiber lasers, benefits of this kind of lasers to 2-μm region and in-band-pumped (two-level system) laser systems are obvious. Advantages of in-band-pumped 2-μm lasers are discussed and analyzed with a simple numerical simulation in terms of Tm-doped fiber lasers. We also propose the key factors in the development of the gain-switched fiber lasers and predict the future tendency.

Cholesteric liquid crystals, consisting of chiral molecules, form self-assembled periodic structures exhibiting a photonic bandgap. Their selective reflectivity makes them well suited for a variety of applications; their optical response is therefore of considerable interest. The reflectance and transmittance of finite cholesteric cells is usually calculated numerically. Evanescent modes in the bandgap make the calculations challenging; existing matrix propagation methods cannot describe the reflection and transmission coefficients of thick cholesteric cells accurately. Here we present analytic solutions for the electromagnetic fields in cholesteric cells of finite thickness, and use them to calculate the transmission and reflection spectra. The use of analytic solutions allows for the accurate description of arbitrarily thick cholesteric cells, which would not be possible with only direct numerical methods.