In this paper, we present an alternative refractive index sensing scheme based on the photonic spin Hall effect (PSHE). We find that the spin splitting induced by the PSHE shows high sensitivity to the refractive index change (RIC) around the Brewster angle.The refractive index of sample is estimated with a precision of the order of 10−5 refractive index unit (RIU) by measuring the spin splitting with weak measurements. Compared with the surface plasmon resonance sensor, this method does not require the noble metal film and keeps the same sensitivity, which is a low-cost alternative to refractive index sensing.
In this paper, we report results of a high precision polarization state measurement of light based on the in-plane spin splitting (IPSS) in optical reflection. The IPSSs in the coordinate (spatial) and momentum (angular) spaces are respectively highly sensitive to the polarization rotation and ellipticity of the incident light at the Brewster angle. By measuring both the spatial and angular IPSSs with different post-selections, the full information of the polarization state (polarization angle and ellipticity) of the incident light can be obtained. Our research may be applied for the precision measurement of polarization-dependent effects.
A special kind of metal nanograting which has excellent performance on polarization state controlling, is fabricated by
means of interference lithography, reactive ion etching (RIE) and two-time-evaporation coating with metal. The MNG
can produce angle-free elliptically polarized light via rolling the direction of grating, so it will have wide and convenient
applications in the systems which need flexible polarization orientation. We fabricate the MNG and test its performances
on polarization state controlling, then we simulate the process with software.
We numerically study the splitting of light beam which carries orbital angular momentum (OAM) through single metal nano-scale hole. A light beam carrying with OAM has a helical phase distribution in the transverse plane, where the electric field has the form: E(r,θ)=E0exp(lθ), and l is the topological charge which denotes the value of OAM. The circular polarization state is corresponding to the spin angular momentum (SAM), where s=+1 represents the left-handed polarization and s=-1 the right-handed polarization. Simulation results show l dependent splitting of beam through nano metal hole. When l is odd, the transmitted far field splits while no splitting happens when l is even. This phenomenon is attributed to the interaction between OAM beam and plasmonic mode of metal nano-hole. It is revealed that different OAM beam can excite different transverse mode in the metal cavity, which means the interaction should obey an OAM section rule. We show that even l can excite transverse mode with zero total AM and odd l can excite transverse mode with non-zero total AM within the hole. Orbital-spin conversion is also revealed in the free wave/plasmon interaction.
Organic solar cells show a commercially viable future duo to their inherent advantages, such as light weight, flexibility,
and so on. Recently, a lot of progress has been made in every domain of organic solar cells. Among these, plasmonic
light trapping is regarded as a promising light management technology for improving the light absorption in organic
active layer. In this work, we numerically investigate the light enhancement in organic solar cell by embedding metal
gratings as electrodes, including the anode and cathode. The absorption enhancement mechanism is analyzed, and the
effects of grating parameters and incident angle are also investigated systematically. The results show the plasmonic
gratings, especially the bottom grating, have an obvious improvement for light harvesting in organic layer, and an optical
enhancement factor about 100% is obtained.
Integral imaging system with soft substrate is proposed and fabricated by lithographic method. The integral imaging
system consists of microlens array and micro-image array. Based on the optical design theory, the geometrical
parameters of the microlens array and micro-image array is calculated and simulated by the software Tracepro.
Furthermore, some experiments are carried out. The microlens array and micro-image array is fabricated on
Polyethylene Terephthalate substrate by lithographic method. After the alignment between the microlens array and the
micro-image array, three dimensional image can be formed over the microlens array. The imaging system is easy to
curve and can be used on some static displays, such as three dimensional display, three dimensional picture and so on.