Top curve: measurement of T_op and T₁ of bulk V2 spins in 4H-SiC at room temperature. A long optical pumping pulse of 1 ms at 785 nm and 36 mw optical power at the fiber output is used and has a fixed temporal position in the sequence. A standard direct detection spin echo sequence (echo) is synchronized with the optical pumping pulse and globally translated in time through the optical pumping pulse, allowing to follow the time evolution of the spin state populations associated to a given EPR transition of the V2 spins (B0 = 3297 G, f = 9.308 GHz, MS3), before, during and after the optical pumping pulse. The data are blue dots, the two monoexponential fit are red continuous lines, providing: T_op = 139 μs and T₁ = 354 μs. Bottom curve: Standard Hahn spin echo decay curve () recorded on one transition of the V2 (B0 = 3297 G, f = 9.308 GHz, MS3), where the spin echo is recorded at various delays 2 τ, the first microwave pulse starting 20 μs after a long optical pumping pulse of 900 μs at 785 nm and with 36 mw of optical power at the fiber output. The data are blue dots, the monoexponential fit is a red continuous line, providing: T₂ = 48 μs. Inset: pulsessequences applied: pink (largest pulse duration on drawing): optical pulse; red (intermediate pulse duration on drawing): microwave pulse; dark (smallest pulse duration on drawing): spin echo for direct detection. The third arrow compared to second one shows which delay parameter vary.