Ultrafast imaging of terahertz electric waveforms using quantum dots

Phys.org  January 4, 2022
Only few imaging schemes can resolve sub-wavelength fields in the THz range, such as scanning-probe techniques, electro-optic sampling, and ultrafast electron microscopy. The intrinsic constraints on sample geometry, acquisition speed and field strength limit their applicability. An international team of researchers (Germany, Australia) harnessed the quantum-confined Stark-effect to encode ultrafast electric near-fields into colloidal quantum dot luminescence. Their approach, termed Quantum-probe Field Microscopy (QFIM), combines far-field imaging of visible photons with phase-resolved sampling of electric waveforms. By capturing ultrafast movies, they spatio-temporally resolved a Terahertz resonance inside a bowtie antenna and unveiled the propagation of a Terahertz waveguide excitation deeply in the sub-wavelength regime. The QFIM approach is compatible with strong-field excitation and sub-micrometer resolution—introducing a direct route towards ultrafast field imaging of complex nanodevices…read more. Open Access TECHNICAL ARTICLE 

Quantum-Probe Field Microscopy (QFIM). Credit: Light: Science & Applications volume 11, Article number: 5 (2022)