Colloquium by Professor Elizabeth BOER-DUCHEMIN (ISMO)

In this talk I will discuss our work where we use a biased tunnelling junction to locally and electrically excite surface plasmons and excitons. The tunnelling junction used may be between the tip of a scanning tunnelling microscope (STM) and a conducting plasmonic sample[1], between an Au nanoantenna and a gold film[2], or between an STM tip and a conducting substrate on which has been deposited a monolayer of a transition metal dichalcogenide (TMD) material[3-5]. Our setup combines ambient scanning probe microscopy (STM/AFM) with an inverted optical microscope, leading to wide-field imaging capabilities. More precisely, thanks to real plane imaging, we can determine from where on the sample the collected light is emitted, while through Fourier plane analysis the emission angle of the light is known, thus providing a powerful tool for the interpretation of the physical phenomena at play. In plasmonics we have used this technique to produce a directional nanosource of light[6], and a cylindrical vector beam[7]. In the area of exciton physics, thanks to this technique we have studied exciton diffusion, the orientation of the transition dipole moments, and the controlled quenching of luminescence [3-5].

[1] T. Wang et al., Nanotechnology, 22, (2011) 175201
[2] D. Pommier et al., ACS Photonics 10,2641 (2023)
[3] D. Pommier et al., Phys. Rev. Lett., 123, (2019) 027402
[4] R. J. Peña Román et al., Phys. Rev. B, 106, (2022) 085419
[5] R. J. Peña Román et al., Nano Letters 22, (2022) 9244
[6] E. Le Moal et al., Nano Letters 13, (2013) 4198
[7] S. Cao et al., Appl. Phys. Lett., 105, (2014) 111103