Industrial Consultancy & Sponsored Research (IC&SR) , IIT Madras
Method Of Subsurface Inscription On Lab Grown Diamonds
Technology Category/Market
Category- Micro and Nano technologies/ Other Technologies
Industry Classification:
Lab grown diamonds
Applications:
Subsurface marking of lab-grown diamonds for authentication, certification, commercial branding, ownership marking and inventory marking.
Market Drivers:
The global lab-grown diamond market was valued at USD 26.38 billion in 2024 and is projected to grow to USD 110.63 billion by 2035, with a CAGR of 13.92%.
Problem Statement
- Lab-grown diamonds offer ethical, sustainable alternatives to mined diamonds, making traceability vital to ensure authenticity and build consumer trust.
- Conventional inscription techniques, like surface laser marking, risk being erased during polishing or manipulated, posing reliability and authenticity challenges.
- Further, Subsurface inscriptions in diamonds were prone to surface damage, microcracks, or lacked precision due to challenges in beam control and crystal hardness..
- There is a need for a precise, damage-free subsurface inscription on diamond with adjustable parameters for high traceability.
Technology
- Utilizes a femtosecond pulsed laser (delivering 10–50 mW at 10 kHz+, enabling high-peak energy for pinpoint marking without thermal damage.
- Olympus 20 ×, 0.5 NA objective lens concentrates the beam to ≤15 μm spot; Aerotech XYZ stage offers micron-scale movement to inscribe at depths even ≥200 μm.
- Scanning speeds from 0.5–5 mm/s and fluences from 1.27–5.10 J/cm² are tuned per engraving type, striking balance between inscription quality and minimal surface impact.
- Integrated CCD camera defines scanning area and monitors inscription, feeding data to control unit for adaptive trajectory corrections, ensuring repeatable, high-fidelity results.
Key Features/Value Proposition
- The invention uses femtosecond laser for precise engraving at the sub surface of diamond to any depth from surface, avoiding graphitization and microcracks observed in the conventional processes.
- Enables the inscription of QR codes and logos that store traceability data, effectively resolving a significant gap in the gemstone verification.
- Advanced marking techniques to enable inscription of logos as small as 30–60 μm, making them difficult to read even under a 10× lens, while QR codes can be reduced to a size of 100 μm.
- Laser settings are programmable, allowing precise control for varied depths and resolutions.
- SEM and Raman mapping confirms no structural damage or transformation occurs up to an optimal depth.
Questions about this Technology?
Contact for Licensing
Research Lab
Prof. MSR Rao
Department of Physics
Prof. Arunachalam N
Prof. Sathyan Subbiah
Department of Mechanical Engineering
Intellectual Property
- IITM IDF Ref 2884
- IN 202441079446 Patent Application
Technology Readiness Level
TRL 5
Technology Validated in Relevant environment