Transcript Slide 1
Raman-excited spin coherences in NV centers in diamond Maria Simanovskaia Experiments Non-degenerate four wave mixing Electromagnetically induced transparency Non-degenerate four wave mixing NV diamond sample has ~30 ppm color centers, has peak optical density of ~0.6 for 1 W/cm2 probe intensity at 15 K Used one dye laser, with acousto-optic frequency shifters Downshifted R1, R2, P from original frequency by 400, 280, and 420 MHz, respectively Intensities of R1, R2, P and repump beam were 1.2, 1.6, 5.6, 10 W/cm2 20 MHz R1 R2 P D S = −1 S=0 120 MHz Fine structure 20 MHz R1 R2 P S = −1 D 120 MHz S=0 S = +1 • Sublevel splitting due to external magnetic field S = ±1 120 MHz 2.88 GHz S = −1 S=0 0G B-field 1050 G Non-degenerate four wave mixing 3.5° intersection angle To complete equivalence: kD = kR2 − kR1 + kP 514.5 nm argon laser used as a repump Protect against spectral hole burning Helmholtz coils Laser beams: linearly polarized, focused by 150-mm focal length lens 15 K maintained by Janis helium-flow cryostat Dye laser Optics Detector Results: NDFWM Narrow linewidth is taken as evidence of Raman process Homogeneous width of optical transition (~50 MHz) Inhomogeneous width of spin transition (5 MHz) Recall: for NDFWM, intensities of R1, R2, P and repump beam were 1.2, 1.6, 5.6, 10 W/cm2 Saturation intensities are 36 W/cm2 and 56 W/cm2 for optical transitions resonant with R1 and R2, respectively Electromagnetically induced transparency Lambda EIT scheme Probe: R2, 1 W/cm2 Used R2, R1 and repump beams Coupling: R1, 280 W/cm2 S = −1 120 MHz S=0 120 MHz Freq. difference R2, with diamond and R1 % Transmission R2, with diamond % Transmission % Transmission R2, no diamond 120 MHz Freq. difference 120 MHz Freq. difference Results: EIT Max value of transparency is 17% of background absorption 70% of what is possible (random orientation of NV center in diamond) EIT linewidth is substantially smaller than laser jitter (~100 MHz) and the optical homogeneous linewidth Thank you!