Signatures of ultrafast electronic and atomistic dynamics in bulk photoluminescence of CVD and natural diamonds excited by ultrashort laser pulses of variable pulsewidth

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

“…However, for the current development of ultrashort pulse laser writing technology in diamonds it is required to envision intensity- and wavelength-dependent photoexcitation mechanisms and electronic dynamics in dense electron–hole plasma, similar to that explored in other dielectrics by time-resolved interferometry [ 43 , 44 , 45 ] and ultrasonics [ 46 ]. In this context, despite the radiative recombination and the related PL being a rather slow and low-rate process during the photoexcitation of diamonds at high fs-laser intensities ( Figure 1 ), it effectively functions as a non-perturbing indicator of EHP density, produced via different photogeneration and recombination processes [ 91 ]. Specifically, UV-range (>350 nm) A-band emission, resulting from radiative recombination of electrons and hopes trapped by donor–acceptor pairs in natural diamonds [ 67 , 87 , 91 ], and deep UV (>230 nm) bands originating from predominating free-exciton radiative recombination in synthetic diamonds [ 66 , 89 , 90 ] ( Figure 5 b), are known to provide the most straightforward insight into the preceding dense EHP dynamics.…”

“…Recently, similar final OCs were observed upon ultrafast laser photoexcitation in natural diamonds highly enriched by different medium-based and highly aggregated OCs, with the overall nitrogen concentration up to 10 3 ppm [ 121 ]. Alternatively, direct intra-center photoexcitation [ 85 , 86 , 87 , 88 , 91 , 122 , 123 ] or indirect excitation via interband EHP photogeneration and succeeding (non)radiative intra-gap relaxation of electrons and holes could take place for different OC states in natural diamonds [ 123 ], potentially resulting in their (partial) dissociation. Comparing to the well-known rich picture of quasi-static thermally and pressure-induced atomistic transformations of OCs in diamonds [ 60 , 61 ], elementary paths of ultrafast photo-induced OC conversion remain almost unexplored.…”

“…The highlighted regions and numbered circles denote the corresponding EHP dynamics regimes #1–#3. Adapted from [ 91 ].…”