Nanolasers And Sensors Based On Surface Plasmons

The applications of surface plasmons(SPs)in the fields of physics,biology,chemistry,energy and environment have been gradually excavated in recent decades.With the development of nanotechnology,the demand for microminiaturization of integrated circuits is increasing,and the diffraction limit has become a major constraint on the development of traditional photonic devices shrinking to smaller sizes.This has become a bottleneck restricting the miniaturization of IC chips,but meanwhile a major opportunity for the new type of photonic devices based on SPs.In this historical turning point,SPs has opened the era of ultracompact high speed on chip optical communication with its unique optical characteristics,which provides reliable technical support for entering the age of quantum information in the future.The researches on active and passive opto-electrical devices based on SPs is of epoch-making significance.In this paper,the research status and development trend in this field are surveyed in detail,and we focus on researches on nanolasers and sensors based on SPs.The main findings are listed as below:(1)We designed and experimentally realized a novel plasmonic laser-like emission.In the experiment,we adopted silver nanorod-insulating layer-semiconductor dielectric waveguide(MIS)hybrid structure,and realized the emission of an approximately plasmonic nanolaser at single nanoparticle level.Silver nanorods with high aspect ratios are functioning like nanoscale Fabry-Perot cavities,which can provide the localization and enhancement of electromagnetic fields.The cadmium selenide(CdSe)nanobelts are used as gain medium to compensate the ohm loss within the silver nanorods.Meanwhile,CdSe nanobelt waveguide itself can also achieve photonic laser emission with proper pump excitation.Based on this composite structure,with the increase of the pump power,the emission from CdSe nanoblet will experience three step transition from spontaneous emission to amplified spontaneous emission and finally reach full laser oscillation.During this process,Silver nanorod located on CdSe nanobelt,as an effective nanoantenna,can effectively extract the waveguide photonic modes in CdSe nanobelt.In this scheme,we can realize 3D localized laser-like emission at silver nanorod 's location,and can also compare the pump threshold conditions between plasmonic laser and photonic laser in the same structure,providing an extra experimental reference frame for the debate on whether metal a friend or foe in laser.This coherent localized light source failed in fully compensate the ohm loss of metal nanoparticle,restricting its applications in plasmonic optical components.However,it is easy to fabricate and can operate at room temperature with low pump threshold,which makes it perform superior in biosensing and imaging as compared to its plasmonic nanolaser couperparts.(2)Based on the MIM structure composited of metallic nanowire-insulate layer-ultrasmooth metallic film(NWOM),we experimentally evaluated its sensitivity functioning as a plasmonic ruler as well as a temperature and humidity sensor by monitoring the cavity plasmon resonance existed in the nano-gap region of the NWOM structure.In the experiment,a PVP polymer layer with a thickness of?2.3 nm was used as insulate layer,which can experience thermal expansion and hygroscopic expansion when its envionmental temperature and humidity increases.The peak shift of the cavity plasmon resonant mode of this NWOM structure with respect to temperature and humidity was measured in situ,and the sensing sensitivity of the NWOM structure to the thickness of the nanogap is analyzed.We have precisely tested out the detection limit of this cavity plasmon sensor to be reaching 0.13 pm for the vertical differential resolutions.We then further experimentally expand its applications in temperature and humidity sensing by accurate temperature control and fine spectrum acquisition,and probing the resolving limit to be 0.07 K and 0.008%,respectively.This sensing sensitivity is higher than the majority researches based on SPR sensors.