Angle- and polarization-independent mid-infrared narrowband optical filters using dense arrays of resonant cavities.

We report design and experimental verification of narrowband mid-infrared optical filters with transmission characteristics that are practically constant over a wide range of incident angles. The filter employs a dense array of dielectric resonant cavities in a metal film, where the transmission of each cavity depends upon localized rather than travelling fields, making the filter fundamentally angle-independent. We show experimentally a transmission around 90% from normal incidence up to 60°.

Experimental Studies and Numerical Simulation of Polypyrrole Trilayer Actuators.

Conducting polymer actuators have shown wide application prospects in the field of biomedical sensors and micro-/nanorobotics. In order to explore more applications in biomedical sensing and robotics, it is essential to understand the actuator static behavior from an engineering perspective, before incorporating them into a design. In this article, we have established the mathematical model of a trilayer polypyrrole (PPy) cantilever actuator and validated it experimentally.

All-reflective ring illumination system for photoacoustic tomography.

Given that breast cancer is the second leading cause of cancer-related deaths among women in the United States, it is necessary to continue improving the sensitivity and specificity of breast imaging systems that diagnose breast lesions. Photoacoustic (PA) imaging can provide functional information during in vivo studies and can augment the structural information provided by ultrasound (US) imaging. A full-ring, all-reflective, illumination system for photoacoustic tomography (PAT) coupled to a full-ring US receiver is developed and tested.

Enhancing Sensitivity of a Miniature Spectrometer Using a Real-Time Image Processing Algorithm.

A real-time image processing algorithm is developed to enhance the sensitivity of a planar single-mode waveguide miniature spectrometer with integrated waveguide gratings. A novel approach of averaging along the arcs in a curved coordinate system is introduced which allows for collecting more light, thereby enhancing the sensitivity. The algorithm is tested using CdSeS/ZnS quantum dots drop casted on the surface of a single-mode waveguide.

Local field enhancement on demand based on hybrid plasmonic-dielectric directional coupler.

The concept of local field enhancement using conductor-gap-dielectric-substrate (CGDS) waveguide structure is proposed. The dispersion equation is derived analytically and solved numerically. The solution of the dispersion equation reveals the anti-crossing behavior of coupled modes.