Permanent optical bleaching in HPHT-diamond via aggregation of C- and NV-centers excited by visible-range femtosecond laser pulses

Up/Down-Scaling Photoluminescent Micromarks Written in Diamond by Ultrashort Laser Pulses: Optical Photoluminescent and Structural Raman Imaging

“…Importantly, such laser-induced modification of the nitrogen impurity centers does not damage the carbon crystalline lattice, as can be seen in the nearly constant 1332 cm −1 optical phonon Raman peak intensity as a function of peak laser power and exposure (Figures 3d-f and 4d,e). It means the micromarks appear blind in the Raman spectra due to the rather delicate laser-induced structural modification, not introducing a considerable permanent amount of transient carbon vacancies (V) and interstitials (I) in the micromarks [18], similar to our other similar studies in natural diamonds [13,14].…”

“…Meanwhile, in natural diamonds with high concentration of nitrogen impurities in different structural forms (N, 2N, NV, 2NV, 3NV, 4NV, 4N2V, etc. [10]) principal atomistic paths of such ultrashort-pulse laser-induced structural reconfiguration of the present centers are still under active investigation [11][12][13][14]. Moreover, structural damage of host carbon lattice in the laser-induced vacancy-mediated mechanism of structural reconfiguration has not been explored yet [4][5][6][7][8], thus hindering potential applications in diamond photonics.…”

“Stealth Scripts”: Ultrashort Pulse Laser Luminescent Microscale Encoding of Bulk Diamonds via Ultrafast Multi-Scale Atomistic Structural Transformations

“…These photogenerated active intrinsic atomistic defects could renormalize the initial abundance of different OCs in diamonds, for example, by locally joining and reconfiguring in the focal volume the present atomic-like substitutional nitrogen (N) C centers in ultrapure (nitrogen content~1 ppb) electronic-grade synthetic diamonds to yield NV centers as single-photon sources [ 11 , 12 , 13 , 14 , 21 , 22 , 23 ]). In contrast, in a nitrogen-enriched (~100 ppm) red-colored synthetic diamond, the opposite occurs; a laser-induced vacancy-driven aggregation process of C and NV centers was recently demonstrated [ 120 ], appearing as its permanent visual bleaching.…”

“…The alternative, bleaching process is of interest in changing ordinary intrinsic colors of natural and synthetic diamonds. Specifically, in the study, we used an Imperial Red Diamonds TM crystal (LLC Velman, Russia), HPHT-produced Ib-crystal (3.5 × 2.2 × 0.9 mm 3 ), red-colored after its e-beam exposure (3 MeV/5 × 1018 cm –2 ) and accompanying atmospheric pressure, high-temperature annealing in vacuum at 1200 °C for 30 min [ 120 ] ( Figure 10 a). The intrinsic impurity concentrations were as follows: C center ~200 ppm, NV − center ~5–6 ppm, interstitial nitrogen atoms N I ~15 ppm, and very minor Ni-catalyst content, with no indications of irradiation-induced neutral (GR, V 0 ) or negatively charged (ND1, V − ) vacancies in FT–IT, optical transmittance, and photoluminescence spectra ( Figure 10 b,c).…”

“…As a result of the two-photon laser-induced bleaching in the visible range [ 120 ], the decrease of NV 0 and NV − center bands, excited at the 405 nm and 532 nm wavelengths, by 2–3 times in the bleached micro-regions regarding the unexposed material, was observed ( Figure 10 c). This accompanied by the minor increase of their PL yield at low-intensity exposures deeper (near the expected focal point) inside the sample and coincided with the enhanced transmission in the main C center and minor A center IR-absorption bands.…”