Imaging-assisted Raman and photoluminescence spectroscopy for diamond jewelry identification and evaluation

Abstract

Jewelry identification and evaluation are limited owing to interference from the surrounding metal mount and adjacent gemstones. To maintain transparency in the jewelry market, this study proposes imaging-assisted Raman and photoluminescence spectroscopy for jewelry measurement. The system can automatically measure multiple gemstones on a jewelry piece sequentially, using the image as a reference for alignment. The experimental prototype demonstrates the capability of noninvasive measurement for separating natural diamonds from their laboratory-grown counterparts and diamond simulants. Furthermore, the image can be used for gemstone color evaluation and weight estimation.

Excimer laser based photoluminescence device for diamond identification

“…Among all types of gemstones, diamond screening and identification present the most critical task due to its high value, necessitating the need for alternative methods to differentiate between different types of diamonds. Conventionally, diamond identification involves the use of various spectroscopic techniques in tandem, such as absorption, Raman and/or photoluminescence (PL) spectroscopy analysis [1][2][3]. The photoluminescence features of diamonds provide essential information about their crystallographic defects [4][5][6][7], and the integration of photoluminescence imaging and spectroscopy information could serve as a clear guidance to separate natural diamonds from their lab-grown counterparts and non-diamond materials.…”

Photoluminescent Microbit Inscripion inside Dielectric Crystals by Ultrashort Laser Pulses for Archival Applications

“…(Sub)microscale laser modification of molecular or crystalline structures and related PL spectra underlies facile and robust encoding of bulk diamonds for their tracing applications in identifying synthetic diamonds between natural ones in large commercial diamond collections [6], protecting trademarks of high-quality natural (potentially, synthetic too) diamond manufacturers [7], limiting commercial trading and marketing of illegal diamonds. This PLbased encoding appears unique in diamonds, where other popular encoding technologiesablation fabrication of (sub)microscale voids [8] or birefringent nanogratings [9,10] -don't work in the ultra-hard diamond lattice, better tending to graphitization [11], while PL read-out is more simple and sensitive.…”

Photoluminescent Microbit Inscripion Inside Dielectric Crystals by Ultrashort Laser Pulses for Archival Applications

“…Ultrashort-pulse lasers proved to work as a versatile tool for time-resolved and/or non-linear spectroscopy [ 6 , 7 ], precise surface nano- and micro-machining of any—absorbing or transparent—materials [ 8 , 9 ], micro-modification and inscription inside bulk transparent media [ 10 , 11 , 12 ]. In the latter case, (sub)microscale laser modification of molecular or crystalline structures and related PL spectra underlies facile and robust encoding of bulk diamonds for their tracing applications in identifying synthetic diamonds from natural ones in large commercial diamond collections [ 13 ], protecting trademarks of high-quality natural (potentially, synthetic too) diamond manufacturers [ 14 ], limiting commercial trading and marketing of illegal diamonds. This PL-based encoding appears unique to diamonds, where other popular encoding technologies—ablation fabrication of optically-contrasted (sub)microscale voids [ 15 ] or ablative birefringent nanogratings [ 16 , 17 ]—do not work in the ultra-hard diamond lattice, tending to be better for graphitization [ 18 ], while PL read-out is simpler and more sensitive.…”