Controlled plasmon-enhanced fluorescence by spherical microcavity

A surrounding electromagnetic environment can engineer spontaneous emissions from quantum emitters through the Purcell effect.For instance,a plasmonic antenna can efficiently confine an electromagnetic field and enhance the fluorescent process.In this study,we demonstrate that a photonic microcavity can modulate plasmon-enhanced fluorescence by engineering the local electromagnetic environment.Consequently,we constructed a plasmon-enhanced emitter(PE-emitter),which comprised a nanorod and a nanodiamond,using the nanomanipulation technique.Furthermore,we controlled a polystyrene sphere approaching the PE-emitter and investigated in situ the associated fluorescent spectrum and lifetime.The emission of PE-emitter can be enhanced resonantly at the photonic modes as compared to that within the free spectral range.The spectral shape modulated by photonic modes is independent of the separation between the PS sphere and PEemitter.The band integral of the fluorescence decay rate can be enhanced or suppressed after the PS sphere couples to the PE-emitters,depending on the coupling strength between the plasmonic antenna and the photonic cavity.These findings can be utilized in sensing and imaging applications.

Review of design principles of 2D photonic crystal microcavity biosensors in silicon and their applications

In this paper, we reviewed the design principles of two-dimensional （2D） silicon photonic crystal microcavity （PCM） biosensors coupled to photonie crystal waveguides （PCWs）. Microcavity radiation loss is con- trolled by engineered the cavity mode volume. Coupling loss into the waveguide is controlled by adjusting the position of the microcavity from the waveguide. We also investigated the dependence of analyte overlap integral （also called fill fraction） of the resonant mode as well as the effect of group index of the coupling waveguide at the resonant wavelength of the microcavity. In addition to the cavity properties, absorbance of the sensing medium or analyte together with the affinity constant of the probe and target biomarkers involved in the biochemical reaction also limits the minimum detection limits. We summarized our results in applications in cancer biomarker detection, heavy metal sensing and therapeutic drug monitoring.

Purcell effect of GaAs quantum dots by photonic crystal microcavities

We fabricate photonic crystal slab microcavities embedded with GaAs quantum dots by electron beam lithography and droplet epitaxy. The Purcell effect of exciton emission of the quantum dots is confirmed by the micro photoluminescence measurement. The resonance wavelengths, widths, and polarization are consistent with numerical simulation results.

Light extraction enhancement of SOI-based erbium/oxygen Co-implanted photonic crystal microcavities

H_5 photonic crystal（PC） microcavities co-implanted with erbium（Er） and oxygen（O） ions were fabricated on silicon-on-insulator（SOI） wafers.Photoluminescence（PL） measurements were taken at room temperature and a light extraction enhancement of up to 12 was obtained at 1.54μm,as compared to an identically implanted unpatterned SOI wafer.In addition,we also explored the adjustment of cavity modes by changing the structural parameters of the PC,and the measured results showed that the cavity-resonant peaks shifted towards shorter wavelengths as the radius of the air holes increased,which is consistent with the theoretical simulation.