No abstract

the collective charge density scattered by a single electron. Hence, the dephasing time significantly affects the field-enhanced intensity of surface plasmon resonance, as well as the intensity magnitude of the nonlinear effect, such as surfaceenhanced Raman scattering, and secondand third-harmonic generation (SHG and THG). [5][6][7][8][9][10][11] To maintain coherent persistence, LSPR can be promoted to surface lattice resonance (SLR) by constructing a repetitive array with a periodicity approaching the LSPR wavelength of nanoparticles, which produces leptokurtic spectral features (referred to as Wood or Rayleigh anomalies). [12][13][14][15] Therefore, in addition to the shape and size of the nanoparticles, the shape and periodic parameters of the lattice inevitably influence the resonance mass and intensity. Highly narrow resonances can be achieved by tuning the lattice constant within manufacturing technology, which has been studied extensively. [15][16][17] However, the surface nonlinearity of two-photon excited fluorescence (2PEF), three-photon excited fluorescence (3PEF), SHG, and THG, which is affected by the lattice resonance, and has been revealed by reflected spectral and inverted microscopic methods, particularly with high sensitivity and high resolution, remains insufficiently understood. The vibration modes of SLR, driven by near infrared (NIR) I (750-1000 nm) or NIR II (1000-1700 nm) lasers on different nanoparticle arrays and significantly enhancing the local fields at the particles, require further exploration. Moreover, employing diverse excitation wavelengths will result in chromatic aberration and resolution reduction, which can be improved by technological means and computational solutions, such as the design of higher NA objectives, localization and tracking of individual fluorescent particles and molecules, [18,19] and modeling of a reliable point spread function. [20] Although saturated structured-illumination microscopy, [21] photoactivated localization microscopy, [22,23] stimulated emission depletion microscopy, [24,25] and multiphoton harmonic spatial frequency modulation imaging [26][27][28] have made tremendous inroads toward approaching or breaking the diffraction limit for multiphoton microscopy, a lack of the determination of optical resolutions for the nonlinear optical imaging of metasurfaces remains. The resolution that can be achieved by a system determines whether it can reveal the lattice resonance on the nanoscale.An ultrafast spectral imaging optical system featuring adaptive precompensation for group delay dispersion, automated tuning and collimation, rapid power stabilization, and rapid spectral imaging switching is developed. In this system, real-time visualization ensures that the excited Gaussian beam remains focused on the nanoarray of the electron-beam lithographed metasurface, as well as maximum gain of the nonlinear effect information. Based on the system, two surface-lattice resonance metasurfaces under broadly tunable excitation (800-1300 nm) are investigated. Th...

Human serum albumin (HSA) is a depot and carrier for many endogenous and exogenous molecules in blood. Many studies have demonstrated that the transport of HSA in tumor microenvironments contributes to tumor development and progression. In this report, we set up a multimodal nonlinear optical microscope system, combining two-photon excitation fluorescence, second harmonic generation, and two-photon fluorescence lifetime imaging microscopy. The fluorescence lifetime of a small squaraine dye (SD) is used to evaluate HSA concentrations in tumor tissue based on specific binding between SD and HSA. We used SD to stain the cryosections from serous ovarian cancer patients in high-grade (HGSOC) and low-grade (LGSOC), respectively, and found a gradient descent of HSA concentration from normal connective tissue to extracellular matrix to tumor masses from 13 to 2 µM for LGSOC patients and from 36 to 12 µM for HGSOC patients. We demonstrated that multimodal nonlinear optical microscopy can obtain similar results as those from traditional histologic staining, thus it is expected to move to clinical applications.

The mortality of high‐grade serous ovarian cancer (HGSOC) accounts for 70% to 80% of all ovarian cancer deaths and overall mortality rate has not declined in the last decade. Recently, many studies have demonstrated that HGSOC originates from the fallopian tubes. The extracellular matrix (ECM) is present in all tissues, its remodeling and interaction with cells are crucial for regulating cell proliferation, migration, and differentiation. In this paper, we used label‐free nonlinear optical microscopy to image tissues of the fallopian tube and ovary. Combining a set of image processing algorithms, we monitored the remodeling of ECM in the fallopian tube and ovary during the invasion of primary serous fallopian tube tumor into the ovary in microscopic dimension. With this approach, we can obtain physiological information of HGSOC at the early stage, which provided useful data for auxiliary clinical diagnosis.