A diamond is valuable not only as a gemstone. It conducts heat well, withstands high voltages and is transparent in visible light, so it is promising for high-power electronics, optics and heat removal from chips. But its exceptional hardness makes it difficult to turn into thin plates of the required shape.
In recent years, lasers have begun to be used to cut diamond. A focused beam creates microscopic changes inside the crystal that guide crack growth. However, scientists still have a poor understanding of how diamonds grown by different methods respond to such exposure.
A study published on November 1, 2026, in the journal Diamond and Related Materials was conducted by a group led by Professor Hirofumi Hidai of Chiba University (Japan). Together with Mahiro Ikeno, they studied how various laboratory diamonds respond to ultrashort laser pulses in order to find a practical way to cut large crystals.
First, three single crystals were compared: one grown by the high-pressure high-temperature (HPHT) method, and the other two by chemical vapor deposition (CVD). Their nitrogen impurity levels differed. The samples were irradiated with focused pulses lasting from 233 femtoseconds (fs; one fs is one millionth of a nanosecond) to 30 picoseconds (ps; one ps is one thousandth of a nanosecond). Then, using microscopy, spectroscopy and image analysis, they studied the size, shape and continuity of the modified regions.
The diamonds behaved differently. CVD samples could be modified with much shorter pulses than the HPHT diamond. In CVD crystals, the shortest pulses left tiny separate marks, while pulses of about 10 ps and longer created more extended regions. Nitrogen content alone did not explain the differences - microscopic defects associated with the growth conditions of each crystal probably play an important role. In addition, in CVD diamonds the changes turned out to be less stable and more varied in shape.
Based on these data, the researchers applied 10 ps pulses to an 8 by 8 mm CVD diamond, creating modified zones in the form of an ordered grid. They did not try to obtain a complete network of cracks at once, but gradually added new regions between existing ones. After four such stages, the crystal easily split along the {100} plane from a light touch with tweezers. This plane is considered the most convenient for polishing, which is important in practice.
The area of the resulting 8 by 8 mm plate was about 710 times the area of the 300-micron HPHT diamond produced in the previous work. This is a notable step toward creating large diamond substrates for optics and electronics.
According to Hidai, the method could find application in the production of diamond substrates and components: optical windows for high-power lasers in lithography systems, heat sinks for advanced chips, including AI accelerators, and diamond-based power semiconductors. The scientists believe the process can be scaled for industry - this will reduce costs and improve material utilization efficiency. In the future, diamond power devices could help reduce energy losses in data centers, power systems and electric vehicles.
It should be emphasized: the study demonstrates the possibility of cutting, but does not prove that the technology is already ready for mass adoption. The authors merely propose a direction for further development.