- 标题
- 摘要
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- 实验方案
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Slide-free imaging of hematoxylin-eosin stained whole-mount tissues using combined third-harmonic generation and three-photon fluorescence microscopy
摘要： Intraoperative margin assessment of surgical tissues during cancer surgery is clinically important, especially in the case of tissue conserving surgery like Mohs micrographic surgery in which minimization of the surgical area is considered crucial. Frozen pathology is the gold standard of assessing excised tissues for signs of remaining cancerous lesions. The current protocol, however, is time-consuming and labor-intensive. Instead of the complex frozen sectioning, staining, and traditional white light microscopy imaging protocol, optically-sectioned histopathological imaging of hematoxylin-eosin stained whole-mount skin tissues with a sub-femtoliter resolution is demonstrated by using nonlinear microscopy in this study. With our proposed method, the reagents of staining and the contrast of imaging are fully consistent with the current clinical standard of frozen pathology, thus facilitating rapid intraoperative assessment of surgical tissues for future applications.
关键词： hematoxylin-eosin,three photon microscopy,third harmonic generation microscopy,surgical border,margin assessment
更新于2025-09-23 15:23:52
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Nonlinear Optics || Quantum-Mechanical Theory of the Nonlinear Optical Susceptibility
摘要： In this chapter, we use the laws of quantum mechanics to derive explicit expressions for the nonlinear optical susceptibility. The motivation for obtaining these expressions is at least three-fold: (1) these expressions display the functional form of the nonlinear optical susceptibility and hence show how the susceptibility depends on material parameters such as dipole transition moments and atomic energy levels, (2) these expressions display the internal symmetries of the susceptibility, and (3) these expressions can be used to make predictions of the numerical values of the nonlinear susceptibilities. These numerical predictions are particularly reliable for the case of atomic vapors, because the atomic parameters (such as atomic energy levels and dipole transition moments) that appear in the quantum-mechanical expressions are often known with high accuracy. In addition, since the energy levels of free atoms are very sharp (as opposed to the case of most solids, where allowed energies have the form of broad bands), it is possible to obtain very large values of the nonlinear susceptibility through the technique of resonance enhancement. The idea behind resonance enhancement of the nonlinear optical susceptibility is shown schematically in Fig. 3.1.1 for the case of third-harmonic generation. In part (a) of this figure, we show the process of third-harmonic generation in terms of the virtual levels introduced in Chapter 1. In part (b) we also show real atomic levels, indicated by solid horizontal lines. If one of the real atomic levels is nearly coincident with one of the virtual levels of the indicated process, the coupling between the radiation and the atom becomes particularly strong and the nonlinear optical susceptibility becomes large.
关键词： resonance enhancement,quantum mechanics,nonlinear optical susceptibility,third-harmonic generation,dipole transition moments,atomic energy levels
更新于2025-09-23 15:21:01
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Quasi-phase-matched third harmonic generation in organic multilayers
摘要： We report the first realization of quasi-phase-matched (QPM) third harmonic generation in isotropic polymer films. Spin-coated thin films of ethyl-violet molecules dispersed in a polymer host (EV) were used as cubic nonlinear optical media because of their transparency at both the fundamental (1230 nm) and the third harmonic (410 nm) wavelengths. A passive layer of a UV-curable material was formed to compensate the phase shift between the two light waves after propagating through each EV layer. We fabricated a series of samples with 1~4 EV layers (0~3 alternatingly coated passive layers). The third harmonic output power showed a quadratic increase with the number of layers, providing a strong evidence for successful quasi-phase-matching. A conversion efficiency of 0.15% was observed with a 190 fs pulse input.
关键词： third harmonic generation,ethyl-violet molecules,quasi-phase-matched,isotropic polymer films,UV-curable material
更新于2025-09-23 15:21:01
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Third and fifth harmonics generation in air and nanoparticle-containing plasmas using 150-kHz fiber laser
摘要： High-pulse repetition rate lasers allow significant enhancement in the average power of the low-order harmonics generation in isotropic media. We report on the third (343-nm) and fifth (206-nm) harmonics generating in air and different nanoparticle-containing laser-produced plasmas by applying Yb-doped fiber laser delivering 37-fs, 100-kHz, 1030-nm, 0.5-mJ pulses. Different characteristics of these processes (power and density dependences, influence of impeding processes, role of synthesized nanoparticles, variations of the spectral modulation of driving pulses, etc.) are analyzed. We compare the formation of the plasmas on the surfaces of aluminum, carbon, manganese, and titanium bulk species, as well as quantum dots of metal sulfides as the media for low-order harmonics generation, using 250-fs (1030-nm) and 5-ns (1064-nm) heating pulses at different delays between the heating and driving pulses. Average power of about 20 mW was estimated for the third harmonic emission from metal plasmas, with 3 × 1016 UV photons (343 nm) emitted per second.
关键词： Third harmonic generation,Fifth harmonic generation,Nanoparticle-containing plasmas,High-pulse repetition rate,Fiber laser
更新于2025-09-23 15:19:57
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Simultaneous effects of pressure, temperature, impurity location, SOI and magnetic field on THG of a pyramid quantum dot
摘要： We have investigated simultaneous effects of pressure, temperature, impurity location, Rashba and Dresselhaus spin–orbit interaction and magnetic field on THG of realized GaAs/Al0.5Ga0.5As pyramid quantum dot with considering the wet layer. For this purpose, we have calculated the energy levels and wave function of one electron that is confined in constant potential, in presence of impurity, magnetic field, Rashba and Dresselhous SOI in various temperatures, pressure and impurity location in effective mass approximation by FEM. In the following, we have presented the effect of magnetic field, Rashba and Dresselhous SOI, temperature, pressure and impurity location on THG in various conditions. Results show that: (1) THG increases by increasing the magnetic field and the distance between the peaks decrease. Also, the peak corresponding to the E21 transition has a blue shift and the peaks corresponding to the E31/2 and E41/3 transitions have a red shift. (2) THG decreases and shifts to higher energies and has a small blue shift by augment of temperature. (3) THG enhances and all of peaks have a red shift by increment of pressure. (4) THG has a minimum around z0 = 4 nm in all magnetic field, temperature and pressure cases. Also, all of peaks have a blue shift by augment of z0 until z0 = 4 nm and then have a red shit by increasing the z0.
关键词： Pyramid quantum dot,Spin orbit interaction,Third harmonic generation
更新于2025-09-23 15:19:57
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Microcavity Nonlinear Optics with an Organically Functionalized Surface
摘要： We report enhanced optical nonlinear effects at the surface of an ultrahigh-Q silica microcavity functionalized by a thin layer of organic molecules. The maximal conversion efficiency of third harmonic generation reaches ～1680%=W2 and an absolute efficiency of 0.0144% at pump power of ～2.90 mW, which is approximately 4 orders of magnitude higher than that in a reported silica microcavity. Further analysis clarifies the elusive dependence of the third harmonic signal on the pump power in previous literature. Molecule-functionalized microcavities may find promising applications in high-efficiency broadband optical frequency conversion and offer potential in sensitive surface analysis.
关键词： Nonlinear Optics,Microcavity,Third Harmonic Generation,Surface Functionalization,Organic Molecules
更新于2025-09-23 15:19:57
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Hot Electrons Modulation of Third Harmonic Generation in Graphene
摘要： Hot-electrons dominate the ultrafast (～fs-ps) optical and electronic properties of metals and semiconductors and they are exploited in a variety of applications including photovoltaics and photodetection. Here we perform power-dependent third harmonic generation (THG) measurements on gated single layer graphene (SLG) and we show that hot-electrons modulate significantly the power-law dependence of THG, inducing a large deviation from the expected cubic power-law. We use a Chemical Vapor Deposition (CVD) SLG sample transferred on Fused Silica (FS) and gated by ionic liquid (IL), Fig.1(a). We excite the sample with the idler beam of an Optical Parametric Oscillator (OPO, Coherent) at a photon energy of ?ω0=0.69eV. The OPO is seeded by a mode-locked Ti:Sa laser (Coherent) with 150fs pulse duration and 80MHz repetition rate. The OPO idler spot-size is～4.7μm and the pulse duration ～300fs.
关键词： Hot electrons,nonlinear optics,third harmonic generation,graphene
更新于2025-09-23 15:19:57
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Methodical engineering of defects in MnXZn1-X O(x?=?0.03, and 0.05) nanostructures by electron beam for nonlinear optical applications: A new insight
摘要： A series of MnxZn1-xO (x = 0.03, 0.05) nanostructures have been grown via the solution based chemical spray pyrolysis technique. Electron beam induced modifications on structural, linear and nonlinear optical and surface morphological properties have been studied and elaborated. GXRD (glancing angle X-ray diffraction) patterns show sharp diffraction peaks matching with the hexagonal wurtzite structure of ZnO thin films. The upsurge in e-beam dosage resulted in the shifting of XRD peaks (101) and (002) towards lower angle side, and increase in FWHM value. Gaussian deconvolution on PL spectra reveals the quenching of defect centers, implying the role of electron beam irradiation regulating luminescence and defect centers in the nanostructures. Irradiation induced spatial confinement and phonon localization effects have been observed in the films via micro Raman studies. The later are evident from spectral peak shifts and broadening. Detailed investigations on the effect of electron beam irradiation on third order nonlinear optical properties under continuous and pulsed mode of laser operation regimes are deliberated. Third order absorptive nonlinearity of the nanostructures evaluated using the open aperture Z-scan technique in both continuous and pulsed laser regimes shows strong nonlinear absorption coefficient β eff of the order 10-4 cm/W confirming their suitability for passive optical limiting applications under intense radiation environments. Laser induced third harmonic generation (LITHG) experiment results supports the significant variation in nonlinearities upon electron beam irradiation, and the effect can be utilized for frequency conversion mechanisms in high power laser sources and UV light emitters.
关键词： Mn:ZnO nanostructures,8MeV e-beam,Spatial confinement effects,Defects quenching,Third harmonic generation
更新于2025-09-19 17:15:36
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Quasi-Phase-Matched Third Harmonic Generation in Periodic Stacks of Polymer Bilayers
摘要： Quasi-phase-matching (QPM) is widely used for nonlinear frequency conversion with quadratic media, in which QPM is achieved by periodically reversing the signs of the nonlinear optical coefficients. Although efficient third harmonic generation (THG) can be realized by cascading two quadratic processes, direct QPM THG with isotropic media is of fundamental interest. For an isotropic cubic medium, however, reversal of the sign of the nonlinearity is not possible. Recently, we reported the first experimental realization QPM THG in isotropic polymer films with alternatingly deposited multilayers of a highly nonlinear organic material and a passive resin up to four periods [1]. Here, we investigated the QPM characteristics by measuring the THG output while tuning the fundamental wavelength around the QPM condition.
关键词： Quasi-phase-matching,third harmonic generation,isotropic polymer films,nonlinear optical coefficients
更新于2025-09-16 10:30:52
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Study of various material particles by third harmonic generation method based on laser pulse induced plasma
摘要： Third harmonic generation (THG) from plasma can be used as probe radiation to characterize the plasma components. In this work, we present the study of the spatiotemporal profile of generated particles in various plasmas produced from bulk targets (C, Cr, In, Ni, Ag, CdS and ZnS) using pulsed laser ablation and THG using 800 nm, 40 fs probe pulses. The dependence of THG on the probe pulse intensity and the distance of the probe beam from the target position are analyzed. The influence of the ejected particle mass on THG with respect to the distance between the target and the probe pulses position was observed. The temporal evolution of THG depended on the delay between heating 6 ns pulses and driving 40 fs pulses. The variation of third harmonic intensity in the plasma components with atomic weight M on the delay (td) was consistent with the kinetic model described by relation td ∞ M0.5. THG from metal targets was mostly originated from the atomic and ionic components in plasma, whereas the clusters and heavier particles were responsible for this process in the case of ablated semiconductor materials.
关键词： Plasma,Laser ablation,Particle characterization,Third harmonic generation
更新于2025-09-12 10:27:22