Diamond’s exceptional hardness makes it difficult to manufacture into the thin, precisely shaped substrates required for high-performance technologies. Researchers at Chiba University in Japan have now demonstrated a laser-based approach that can split a lab-grown diamond along the {100} crystal plane, an orientation considered especially practical because it is easier to polish.
The study, published in Diamond and Related Materials on Nov. 1, 2026, examined how three single-crystal diamonds responded to ultrashort laser pulses. One sample had been produced using the high-pressure high-temperature (HPHT) method, while two others were made through chemical vapor deposition (CVD) and contained different levels of nitrogen impurities.
The team, led by Professor Hirofumi Hidai and co-authored by Mahiro Ikeno, used focused pulses lasting between 233 femtoseconds and 30 picoseconds. Optical microscopy, spectroscopy and image analysis were then used to assess the size, shape and continuity of the modified regions formed inside the crystals.
The samples showed different responses. The CVD diamonds could be modified with shorter pulses than the HPHT diamond. In the CVD samples, the shortest pulses created small, separated marks, while pulses of around 10 picoseconds or longer generated more continuous modified regions. Nitrogen concentration alone did not account for the differences, indicating that microscopic defects linked to each crystal’s growth history may also be important.
The CVD diamonds generally produced less stable modified regions than the HPHT sample and showed greater variation in their shapes. Using these findings, the researchers selected 10-picosecond pulses to process an 8 mm × 8 mm CVD diamond in a controlled grid.
Instead of creating an entire crack network in a single operation, they added further modified regions midway between existing ones in four successive processing steps. The diamond then split cleanly along the {100} plane after a light tap with tweezers.
The resulting slicing area was approximately 710 times larger than the 300-micrometer-square HPHT diamond produced by the researchers in an earlier study. The team says the larger area is a step toward manufacturing the bigger diamond substrates needed for optical components and electronic devices.
Potential uses include diamond substrates, high-power laser optical windows for lithography systems, heat spreaders for advanced devices such as AI chips and diamond-based power semiconductors. According to Hidai, the process could eventually be adapted to industrial production, potentially reducing manufacturing costs and improving material use.
The study also identifies possible sustainability benefits from wider use of diamond-based power devices. Such components could help reduce energy losses in areas including data centers, power infrastructure and electric vehicles.
Sources: Phys.org.