FmicroscopicAngular resolution spectroscopyspectrumceremony

Angle resolved spectroscopy, as the name suggests, is a technology that can simultaneously detect signal light spectra and emission angles. It is accompanied by microcavity photonics and artificial methodsmetamaterialThe development and application of new micro nano photon materials such as metasurfaces have given rise to novel spectroscopic detection techniques. We know that when light propagates in materials, its dispersion relationship changes due to the interaction between light and matter. Traditional optical detection methods can only detect the energy (frequency) of light, while the momentum of light is affected（k）Information cannot be obtained. Through research, it has been found that the momentum of photons is closely related to the angle of emission (θ) of photons from the material surface. Therefore, by detecting light emitted from different angles on the material surface with angle resolution, optical microcavities can be described,metamaterialWaiting for photon energy in materials and devices(E)-Momentum（k）Relationship, namely dispersion relationship, is studied in depth to investigate its optical properties.

The detection principle of angle resolved microspectroscopy utilizes optical Fourier transform technology,Through Fu Li Ye YeThe imaging method involves imaging different angles of light at once on the detector. The optical principle is shown in the following figure. The light emitted from the surface of the sample at different angles is converged by the microscope objective to the Fourier plane placed behind it. It can be imagined that the light emitted at different angles will be collected at different positions on the Fourier plane, thus achievingfrom the perspectiveConversion to spatial position. Later, through an achromatic imaging system,Spread Fu Li Ye YeImaging at the entrance slit of the spectrometer, after energy resolution by the spectrometer, willCCDDisplay the dispersion plot of spatial position (i.e. angle) and wavelength (i.e. frequency).

image1. Schematic diagram of angle resolution imaging principle

Application case:

1. Mode analysis of photonic crystal coupled cavity

Based on angle resolved fluorescence spectroscopy technology, the symmetry of photonic crystal modes is characterized, and the far-field angular fluorescence distribution of quantum dots embedded in photonic crystals is measured experimentally. The experimental data is in good agreement with the predictions of Young's interference and numerical simulation. In addition, photon eigenvalues with vector propertiesModel performanceThe complex parity of different polarizations does not yet have corresponding physical characteristics within the framework of quantum mechanics.（References:F.Contentset al.,PRL106,143901(2011)）

image2. Photon microCavity moleculeSchematic diagram of emission modes for two coupling modes in China. The diamond represents the electric field distribution of two modes, and highlights the positive (red) and negative (blue) amplitudes with color codes. The red (blue) dashed line represents the constructive (destructive) optical path in the far-field emission pattern.

image3. singleD2Cavity;(a)In orthogonal polarization channelsPLSpectral analysis;(b)SEMImage;(c)–(e)electric fieldFDTD NFFigure;(f)–(h)experimentPLFar-field intensitykSpatial distribution;(i)–(k)FDTDFar-field intensitykSpatial distribution.

2. Metasurfaces and TwoDimension Materialcoupling

Studied the relationship between monolayer and angle resolved reflectance microscopy using angle resolved reflectance spectroscopyMoS2Strong excitation in integrated silver nanodisk array子-Plasma interaction. observed77 KTime-dependent exciton-waitPlasmon couplingHigh intensity58 meVIt can also exist at room temperature. Strong coupling involves three types of resonances, including:MoS2ExcitonsSingle silverLocalized surface plasmon resonance of nanodisks（LSPR）Resonance of plasma lattice with nanodisk array. Experiments have shown that adjusting the geometry of the plasma lattice can effectively control excitons-Plasmon couplingThe strength, polaron composition, and dispersion make it possible for this system to achieve novel two-dimensional plasma polarization devices.(Reference:W.J.Liuet al.,Nano Lett.16,2,1262(2016)）

image4. single layerMoS2upTypical SilverNano disk lattice patternSEMimage

image5. The diameter range of the disc is100nmto170nmAnd the cycle is460 nmofSi/SiO2Angle resolved differential reflectance spectra of five patterned plasma lattices on a substrate. The white dashed line represents the wavelength of the localized surface plasmon resonance mode, and the red dot corresponds to the inclination position obtained by cutting the line to resolve the reflectivity from a constant angle. The blue solid line isFitting results obtained from the coupled oscillator model

3. Angular resolved spectroscopy in Bragg flat microcavitiesVCSELApplications in Devices

Study on Bragg flat optical microcavities using angle resolved white light reflectance spectroscopyDBROptical mode（a-c）Study on the decrease of electron hole Fermi surface under high excitation state by angle resolved fluorescence dynamic spectroscopyCheng, and dispersion evolution of resonance modes in optical systems（d）. Based on mature technologyIII‐VA family of semiconductor flat microcavities, combined with quantum modulation by adjusting the power density of pump lightpitThe strong nonlinear response caused by photogenerated charge carriers can regulate the frequency, momentum, emission time, and pulse width of the emitted laser.(Reference:W.Xieet al.,Optica,3,12(2016)）

image6. Standard non chiral dyesBroadband steady state and time in low viscosity and high viscosity aqueous solutionsDistinguish AllStokes vector spectroscopy

4. Application of Angular Resolution Spectroscopy in Grating Structures

Studied by angle resolved white light reflectance spectroscopyOne dimensional zinc oxide micro rod on silicon-based grating substrate（a）The excitonPolariton mode dispersionCondensation behavior in momentum space（b）, as well as the lifetimes of different energy states（c）. Due to the modulation effect of the grating substrate, the originally continuous optical mode splits, forming a similar patternThe Brillouin zoneCapable of carrying structures. After increasing the particle density,Polarized polaritonsCondensation does not occur at the zero point of momentum space, but rather atBrillouin zone boundaryIn terms of attitude. This is because the self-assembly of micro area samples introduces a structural potential field, which adjusts the spatial distribution and energy state lifetime of particles to achieveNon zero momentumThe condensation of energy states.(Reference:L.Zhanget al.,PNAs, 112, 13 (2015)）

image7. Research on one-dimensional zinc oxide micro rods on silicon-based grating substrates