Here we present design and fabrication of dielectric and plasmonic surfaces and several of their applications in biomolecular sensing. First, a metal-insulator-metal plasmonic surface is presented as a broad band absorber and field enhancer that finds application in Surface enhanced Raman Spectroscopy (SERS). Self-assembled silver nanoislands are formed on a silver reflector with a dielectric spacer in a lithography free process, and allows single molecule level SERS enhancements, resulting in observation of single molecules on a Mobile phone. Another example of plasmonic biosensing is grating coupled plasmonic surfaces for label-free biosensing. Using optical BluRay discs as a template, such plasmonic surfaces are shown to enable plasmonic imaging and multiplex sensing on a Mobile phone, using a custom designed attachment. Also, a plasmonic configuration that is inherently insensitive to the background refractive index is presented.

The modulator using organic electro-optic (EO) polymers has excellent optical properties such as high-speed operation and low driven voltage. The modulator using EO polymer were previously proposed and demonstrated at communication wavelength. We prepared the EO polymer to demonstrate the modulator operated at visible wavelength. Our synthesized EO polymer has low optical loss at operating wavelength. The Mach-Zehnder modulator was fabricated to evaluate modulation properties. In this study, we successfully demonstrated the highly efficient modulator using EO polymer at visible wavelength.

Domain walls (DWs) in ferroelectric materials are of highest interest as integrated functional elements, for instance in optoelectronic nanodevices. We investigated individual ferroelectric DWs in periodically-poled LiNbO3 single crystals by applying polarization-sensitive optical coherence tomography (PS-OCT). Comparing our experimental results with circular light polarization to simulations, we conclude that the three different signals recorded from each DW are associated to both the ordinary and extraordinary refractive index, and to a third contribution that arises from the mean value of the two. PS-OCT hence provides a valuable tool to probe the relevant electro-optical properties close to and at the DWs.

Bound states in the continuum (BICs) in dielectric metasurfaces have gained significant interest for their narrow linewidths and potential applications to high-powered lasers, filters, and sensors. The resonant frequency of a BIC may be tuned by altering its dielectric environment either by changing the substrate or introducing a tunable material such as graphene. In this work, we use a gradient-descent based optimization approach to design 1D BIC metasurfaces with optical modes that exhibit extreme resonant frequency dependence on their dielectric environment. We then experimentally test our predictions by fabricating the structures, measuring their optical response, and comparing to our predictions.

We predicted and demonstrated third harmonic generation in the opaque spectral range of As2S3 glass, enabled by phase-locking between the fundamental and third harmonic waves. We experimentally demonstrate and report near-infrared to ultraviolet frequency conversion enhanced by the excitation of a broad Mie resonance near 1050 nm from an As2S3-based metasurface. Further enhancement of the nonlinear process in the opaque regime of As2S3 can be realized from utilizing high quality factor resonance from quasi-bound states in the continuum and strongly localized modes at band-edges from three-dimensional nanostructure.

Laser hosts with low maximum phonon energies decrease multiphonon-relaxation (MPR) rates, which enables rare earth emission transitions in the mid-IR region. In this work, a comparative study of mid-IR (3-5 µm) spectroscopic properties on Ho3+ ions doped in various low-phonon fluoride (LaF3, BaF2, NaYF4) and chloride (KPb2Cl5, CsCdCl3, CsPbCl3) based crystals were explored. Experimental results of the mid-IR emission properties using both steady-state and time-resolved fluorescence spectroscopy will be presented. Several laser relevant spectroscopic parameters for the 3.9 µm mid-IR emission of all the studied crystals were determined and compared.

We have developed a static Fabry Perot based filter array operating in the mid-infrared range from ~2 to 4.5 μm, matching the absorption region of several volatile organic compounds. Each filter consists of a cavity system formed by two distributed bragg reflectors with a tuning element with varying length in between. The filters with high transmission (>80%) and controllable transmission peak width are integrated with an array of pyroelectric detectors. The robustness, easy-fabrication and the possibility to tune the optical response to a specific application make the integrated filter arrays suitable for compact sensing systems.

We report on an optical fiber based iodine vapor spectroscopy cell. The formed photonic microcell (PMC) is a standalone FC/APC connectorized Iodine filled hollow core photonic crystal fiber (HCPCF) demonstrating transmission efficiency as high as 75% (1.2 dB insertion loss) and an absorption contrast reaching 70% on the P(33) 6-3 transition (i.e. ~633 nm wavelength) at room temperature. Iodine exhibits an astounding amount of transitions on the green-red spectral range. Hence, as a demonstration of its application as a frequency reference, we have generated many sub-Doppler spectral transparencies over the 631-635 range using saturated absorption spectroscopy for laser frequency stabilization.

The glass materials have promoted many scientific, artistic and cultural advancements in the past few hundred years with their unparalleled multi-functional capabilities. Glass optical fibers have enabled the optical communications revolution, which are the backbone of the Internet. Glasses are used for TV, automobile, as well as our smart phones, which completely changed our lives. Glasses are the gain media for fiber lases and high pulse energy solid-state lasers. A brief review of glasses for photonic applications will be presented by Shibin Jiang, AdValue Photonics, Chair of Technical Committee TC20 : Photonic glasses and optical fibers, International Commission on Glass (ICG).