Quantum Optical Effects And Their Applications In The Nanooptomechanical Systems Based On Bilayer-Graphene And NV Center In Diamond

A nitrogen atom substitutes a carbon in diamond and connects with a carbon vacancy nearby,which constitute a NV center in diamond.It has excellent properties,such as bio-compatibility,photostability,chemical inertness.Most importantly,the NV center spin is a solid quantum bit with long spin coherence and relaxation times at room temperature.We can easily manipulate the spin with optical or magnetic resonance methods.Lots of scientists show great interests in NV center in diamond as for these remarkable properties.In the meantime,owing to the development of nanoscience and technology,all kinds of nanostructures related to carbon atoms,such as single/bilayer structure of graphene and microcantilever of diamond,nanobeam of diamond are successfully producted.Due to the atomic structure of diamond and its performance of material mechanics,the nanomechanical resonators made by diamond have outstanding properties,such as super light quality,high quality factor,ultrahigh frequency of the mechanical and intrinsic perfect characteristics.As a consequence,it provides a perfect medium for quantum optical detection of micro-nano scale.In this work,we will employ the pump-probe technique,and mainly introduces several kinds of bilayer-graphene and NV center spinbased nanooptomechanical systems.Then,on the base of their quantum optical effects,we theoretically employ them to make novel graphene-based optical modulators and switches,and to measure the mass,force and detect the Majorana fermions sensitively.The main achievements are as follows:(1)We have theoretically investigated the nonlinear coherent optical properties of a tunable bilayer graphene with the optical pump-probe technique.The distinct linear/nonlinea optical absorption and the optical Kerr effect have been demonstrated in this tunable bilayer graphene.Furthermore,the nonlinear optomechanical properties in this bilayer graphene can be tuned by electrical gating conveniently,which predict its potential applications in novel graphene-based optical modulators and switches.(2)In combination with the pump-probe technique and the spin resonance spectrum,we theoretically propose a realistic,feasible,and an exact way to measure the cantilever's frequency in a hybrid spin-micromechanical cantilever system.Further,we develop this hybrid spin-micromechanical system to be an ultrasensitive mass sensor,which can be operated at300 K with a mass responsivity 0.137Hz/ag for accurate sensing of gaseous or aqueous environments,chemical vapors,and biomolecules.And the best performance on the minimum detectable mass can be 28.7zg in vacuum.We also illustrate an in situ measurement to accurately detect Angiopoietin-1,a marker of tumor angiogenesis.Then,combined with the nanoparticle-enhanced technique,even only one base pair mutation in the target DNA sequence can be identified in real time accurately.Furthermore,based on the spin-microcantilever optomechanical system,we present a proposal for a hybrid NV center spin-double nano-resnonators optomechanical system,which has stronger characteristic peaks and narrower bandwidth,so that the minimum detectable mass can be 14 yg at300K.(3)We theoretically propose an ultrasensitive optical pressure sensor at room temperature,based on a single nitrogen-vacancy(NV)center spinmicrocantilever optomechanical system.In the proposal,we find that the peak-splitting in the spin optical readout spectrum depends linearly on the pressure P induced strain-spin coupling strength.Consequently,the pressure P loaded above NV spin can be measured exactly via the ”Rabisplitting”.(4)Motivated by Stevan's recent experimental progress towards the detection and manipulation of Majorana fermions,we present a novel proposal based on a single nitrogen-vacancy(NV)center spin embedded in ultrapure diamond substrate to probe Majorana fermions in an all-optical domain.With this scheme,a possible distinct Majorana signature is investigated via the electron spin resonance spectrum.The NV center spin can be considered as a sensitive probe,while the SCD microcantilever works as a phonon cavity.It can enhance the probe generated by NV center and Majorana fermions,which makes the Majorana fermions more sensitively to be detected.In our optical scheme,the signal change in the spin resonance spectrum is a possible signature for the MFs and the detection system has non-contact with Majorana fermions.