Physicists at the University of California, Irvine published an article in Science, revealing that they used hydrogen molecules as quantum sensors in scanning tunneling electron microscopy to detect the chemical properties of substances with unprecedented time and space resolution.
The above figure shows that a hydrogen molecule is located between the silver probe tip and the sample in an ultra-vacuum scanning tunneling electron microscope. When the hydrogen molecule is excited by a femtosecond (negative 15th second of 1) terahertz laser, the hydrogen molecule transitions from the ground state to the excited state, and then returns to the ground state within several tens of picoseconds (negative 12th second of 1). This kind of oscillation can be circulated to trigger a rectified current, which enables scientists to obtain the superposition of two states, so as to observe the interaction between hydrogen molecules and the environment.
When the scanning tunneling electron microscope works, the hydrogen molecule becomes a part of the electron microscope, so it acts as a very sensitive sensor, which enables the observer to observe the resolution of .1 angstrom (1 minus 1 cubic meters). The spatial resolution at atomic level and the temporal resolution at femtosecond level allow the observer to see the charge distribution on the sample. This technology can be applied to the detection of two-dimensional matter, and has broad application prospects in advanced energy systems, electronics, quantum computers and other fields.