Figure 1
From: Dynamical sensitivity control of a single-spin quantum sensor
NV centre system and Dynamical sensitivity control (DYSCO) spin dynamics. (a) Energy level scheme of the NV centre an electron spin in the ground state triplet. (b) Top: Schematic representation of a DYSCO 4 · π-pulse unit. Bottom: Simulations and experimentally traced spin vector trajectory for one 4 · π-pulse unit represented on the Bloch sphere spanned by |0〉 and |−〉. The green trajectory in simulations depicts spin evolution when sequentially driven by 4 · π-pulse and vanishing RF field B RF = 0. The coloured trajectories in the simulations and experiment are shown for B RF ≠ 0. Individual π-pulses are shown in red, blue, magenta and cyan dots and traces. (c) Schematic of the DYSCO method and the expected changes in the final state population P 0 for different values of the B RF field amplitude shown in comparison to the Hahn-echo sensing method (note the last π/2 pulse used in NV-metrology based on free-precession/interferometry (bottom) is not required in the DYSCO scheme (top) distinguishing the sensing mechanism of DYSCO). (d) Explicit calculation of the level occupancy P 0 and its dependence on the B RF field and the phase angle φ of the driving pulses at the end of the pulse sequence for N = 1 (the B RF field is given in units of Ω−).
