LAMP-SEMINAR

Understanding and harnessing the way light interacts with matter is at the heart of nanophotonics. The interaction of light with nanoscale matter depends crucially on the material properties like the shape, size, and dielectric permittivity. By tuning the wavelength of incident light to match the resonant modes of the nanostructures we can enhance significantly the scattering or absorption of light. This ability to control lightmatter interaction has enabled a broad range of applications, from the development of nanoscale heat sources to single molecule detection.

In the first part of the talk, I will discuss how resonant scattering and the resulting electric-field enhancement around nano- and micro-cavities can be exploited to amplify and direct molecular emission. Using metal-film–coupled plasmonic nanowires and dielectric microspheres as examples [1,2], I will demonstrate the strengths of wavevector imaging and spectroscopy (also known as back-focal-plane imaging and spectroscopy) in revealing the rich polarization structures of these systems. I will also briefly address the potential for achieving strong molecule–cavity coupling in these systems down to the monolayer limit [3,4].

In the second part of the talk, I will shift the focus to our efforts to understand, engineer, and utilize light absorption in metallic nanostructures as a means of generating nanoscale heat. I will highlight our use of the quantitative phase imaging techniques like the optical diffraction tomography, to visualize 3D non-steady-state thermal fields [5,6].

References:

[1] A.B. Vasista et.al., Nano Lett., 18, 650-655 (2018)

[2] A.B. Vasista et.al., Adv. Opt. Mater., 6, 1801025 (2018)

[3] A. B. Vasista et.al., Nano Lett., 20, 1766-1773 (2020)

[4] A.B. Vasista et.al., Nano Lett., 22, 6737-6743 (2022)

[5] A.B. Vasista et. al., Sci. Adv., 10, eadk5440 (2024)

[6] F. Schmidt, A. B. Vasista et.al., under preparation (2025)