Nanophotonic device building blocks, such as optical nano/microcavities and plasmonic nanostructures, lie at the forefront of sensing and spectrometry of trace biological and chemical substances. A new class of nanophotonic architecture has emerged by combining optically resonant dielectric nano/microcavities with plasmonically resonant metal nanostructures to enable detection at the nanoscale with extraordinary sensitivity. Initial demonstrations include single‐molecule detection and even single‐ion sensing. The coupled photonic‐plasmonic resonator system promises a leap forward in the nanoscale analysis of physical, chemical, and biological entities. These optoplasmonic sensor structures could be the centrepiece of miniaturised analytical laboratories, on a chip, with detection capabilities that are beyond the current state of the art. In this paper, we review this burgeoning field of optoplasmonic biosensors. We first focus on the state of the art in nanoplasmonic sensor structures, high quality factor optical microcavities, and photonic crystals separately before proceeding to an outline of the most recent advances in hybrid sensor systems. We discuss the physics of this modality in brief and each of its underlying parts, then the prospects as well as challenges when integrating dielectric nano/microcavities with metal nanostructures. In Section 5, we hint to possible future applications of optoplasmonic sensing platforms which offer many degrees of freedom towards biomedical diagnostics at the level of single molecules.

Quantum‐enhanced sensing and metrology pave the way for promising routes to fulfil the present day fundamental and technological demands for integrated chips which surpass the classical functional and measurement limits. The most precise measurements of optical properties such as phase or intensity require quantum optical measurement schemes. These non‐classical measurements exploit phenomena such as entanglement and squeezing of optical probe states. They are also subject to lower detection limits as compared to classical photodetection schemes. Biosensing with non‐classical light sources of entangled photons or squeezed light holds the key for realizing quantum optical bioscience laboratories which could be integrated on chip. Single‐molecule sensing with such non‐classical sources of light would be a forerunner to attaining the smallest uncertainty and the highest information per photon number. This demands an integrated non‐classical sensing approach which would combine the subtle non‐deterministic measurement techniques of quantum optics with the device‐level integration capabilities attained through nanophotonics as well as nanoplasmonics. In this back drop, we review the underlining principles in quantum sensing, the quantum optical probes and protocols as well as state‐of‐the‐art building blocks in quantum optical sensing. We further explore the recent developments in quantum photonic/plasmonic sensing and imaging together with the potential of combining them with burgeoning field of coupled cavity integrated optoplasmonic biosensing platforms.

We experimentally investigate the formation of reconfigurable three-dimensional (3D) nonlinear photonic lattices in an externally biased cerium doped strontium barium niobate photorefractive crystal by a spatial light modulator-assisted versatile simplified single step optical induction approach. The analysis of the generated 3D nonlinear photonic lattices by plane wave guiding, momentum space spectroscopy, and far field diffraction pattern imaging is presented, which points to the embedded potential of these 3D structures as reconfigurable platform to investigate advanced nonlinear light-matter interaction in periodic structures.

We present a novel single-step fabrication approach, based on optical phase engineering, for tunable complex photonic chiral lattices of diverse geometries in a large area. By means of engineered reconfigurable phase patterns, we computationally simulate as well as experimentally investigate these complex structures. We show the generation of both periodic right- and left-handed chiral structures as well as photonic transversely quasi-crystallographic chiral structures. These complex chiral lattices are also demonstrated in a photorefractive material, and the lattice formation is analyzed by plane-wave-guided imaging as well as diffraction pattern imaging. Furthermore, complex photonic chiral structures with engineered tunable relative phase shifts between adjacent spiral units realizable in a single step are explored and analyzed.