Nonlinear Optics for Nanoparticle Tracking and Materials Characterization
A high-speed 3D imaging method is developed by integrating ultrafast laser pulse shaping, temporal focusing microscopy and defocused imaging. This system does not require mechanical movement of either the stage or laser beam. Axial scanning is achieved by manipulation of group velocity dispersions on the femtosecond laser spectrum via pulse shaping method by applying modulation functions on an acoustic optical modulator which diffracts the laser spectrum. The scanning depth becomes only dependent on electronic signals which can be tuned to kHz speeds. The volumetric high-speed scanning capability was demonstrated on fluorescent microspheres suspended in a volume of 100 x100 x 80 µm3. Powder samples of RbxCs1-XH2PO4 were synthesized with 10% intervals of Rb (0 ≤ x ≤1). Powder XRD performed shows three major structures between the various samples: monoclinic P21/m for x ≤ 0.5, monoclinic P21/c for x = 0.8, tetragonal I-42d for x ≥ 0.9, and a polymorphic distribution of these structures in the x = 0.6 & 0.7 samples. Second Harmonic Generation (SHG) microscopy and SHG – polarization microscopy was performed and a unique quadruple dependence on polarization was found and correlated to a monoclinic p21/c structure unique to the x = 0.8 sample. SEM/EDS analysis supports the polymorphic distribution of structures seen in the x = 0.6 & 0.7 samples.
Aguilar, Angela Christina, "Nonlinear Optics for Nanoparticle Tracking and Materials Characterization" (2019). ETD Collection for University of Texas, El Paso. AAI13863998.