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Steering second-harmonics
摘要： The phase control and shaping of the second-harmonic radiation generated from an AlGaAs nanodisk antenna has now been accomplished by a team of researchers from Italy, France and Australia. Lavinia Ghirardini and co-workers used electron-beam lithography to fabricate a pair of gratings located either side of a nonlinear nanoantenna. Phase engineering then made it possible to redirect and control the emission angle of second-harmonic light generated from the optically pumped structure. The precise angle of emission can be engineered by employing gratings with different symmetry, or by varying the polarization of the optical pump beam. The control of the emission direction is important because it means that two orders of magnitude more power can be collected out of the antenna plane and arbitrary emission angles could be useful for certain applications. Another key point is that the AlGaAs structures can exhibit lower losses than metallic nanoantennas, which aid efficiency. Such efficient shaping of the nonlinear beams may have applications to, for example, single-photon sources and nonlinear imaging.
关键词： phase control,AlGaAs,nanoantenna,second-harmonics,nonlinear imaging
更新于2025-09-23 15:21:01
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Intraoperative visualization of the tumor microenvironment and quantification of extracellular vesicles by label-free nonlinear imaging
摘要： Characterization of the tumor microenvironment, including extracellular vesicles (EVs), is important for understanding cancer progression. EV studies have traditionally been performed on dissociated cells, lacking spatial information. Since the distribution of EVs in the tumor microenvironment is associated with cellular function, there is a strong need for visualizing EVs in freshly resected tissues. We intraoperatively imaged untreated human breast tissues using a custom nonlinear imaging system. Label-free optical contrasts of the tissue, correlated with histological findings, enabled point-of-procedure characterization of the tumor microenvironment. EV densities from 29 patients with breast cancer were found to increase with higher histologic grade and shorter tumor-to-margin distance and were significantly higher than those from 7 cancer-free patients undergoing breast reduction surgery. Acquisition and interpretation of these intraoperative images not only provide real-time visualization of the tumor microenvironment but also offer the potential to use EVs as a label-free biomarker for cancer diagnosis and prognosis.
关键词： extracellular vesicles,label-free nonlinear imaging,breast cancer,intraoperative imaging,tumor microenvironment
更新于2025-09-04 15:30:14