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Plasmonic structures have been widely employed to manipulate the light coupling of infrared detectors to enhance sensitivity and achieve multidimensional light field recognition. Recently, cavity coupled plasmonic resonators as an improved version of plasmonic light coupling structures have received much attention. A variety of ordinary plasmonic structure integrated infrared detectors and cavity coupled plasmonic resonator integrated infrared detectors are reviewed. Compared with ordinary plasmonic structures, cavity coupled plasmonic resonators are more effective in adjusting the light in-coupling efficiency, local field polarization, and light absorption competition, which is beneficial to performance enhancement in infrared detectors. Several features of cavity coupled plasmonic resonator integrated infrared detectors, including deep subwavelength light concentration with high efficiency, Ohmic loss suppression, high-contrast polarization discrimination, are discussed. As a brief outlook, cavity coupled plasmonic resonators for infrared detectors are expected to have optical-electrical joint functions, be compatible with focal plane array technology, and have new features stemming from innovative combinations of different kinds of cavities and plasmonic structures.

We report the experimental observation of lateral shearing optical gradient forces in nanoelectromechanical systems (NEMS) controlled dual-coupled photonic crystal (PhC) nanobeam cavities. With an on-chip integrated NEMS actuator, the coupled cavities can be mechanically reconfigured in the lateral direction while maintaining a constant coupling gap. Shearing optical gradient forces are generated when the two cavity centers are laterally displaced. In our experiments, positive and negative lateral shearing optical forces of 0.42 nN and 0.29 nN are observed with different pumping modes. This study may broaden the potential applications of the optical gradient force in nanophotonic devices and benefit the future nanooptoelectromechanical systems.

Fano resonance is a prevailing interference phenomenon that stems from the intersection between discrete and continuum states in many fields. We theoretically and experimentally characterize the asymmetric Fano lineshape in side-coupled waveguide Fabry–Perot and photonic crystal nanobeam cavities. The measured quality-factor of the Fano resonance before tuning is 28 100. A nanoelectromechanical systems bidirectional actuator is integrated seamlessly to control the shape of the Fano resonance through in-plane translations in two directions without sacrificing the quality-factor. The peak intensity level of the Fano resonance can be increased by 8.5 dB from 60 nW to 409 nW while the corresponding dip intensity is increased by 12.8 dB from 1 nW to 18 nW. The maximum recorded quality-factor throughout the tuning procedure is up to 32 500. Potential applications of the proposed structure include enhancing the sensitivity of sensing, reconfigurable nanophotonics devices, and on-chip intensity modulator.

In this Letter, we report a hybrid system consisting of nano-optical and nano-mechanical springs, in which the optical spring effect works to adjust the mechanical frequency of a nanoelectromechanical systems resonator. Nano-scale folded beams are fabricated as the mechanical springs and double-coupled one-dimensional photonic crystal cavities are used to pump the “optical spring.” The dynamic characteristics of this hybrid system are measured and analyzed at both low and high input optical powers. This study leads the physical phenomenon of optomechanics in complex nano-opto-electro-mechanical systems (NOEMS) and could benefit the future applications of NOEMS in chip-level communication and sensing.

Titanium doped sapphire (Ti:Al2O3) shows a 420 nm blue emission band whose corresponding excitation band lies at 244 nm. With the aim of ascertaining the origin of this blue emission, using synchrotron radiation we measured the vacuum ultraviolet to ultraviolet absorption spectrum of titanium doped sapphire. It is suggested that the blue emission is due to a center other than a trivalent Ti3+ ion or a tetravalent Ti4+ ion, most probably an F+‐type color center formed in the crystal.