This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: When we think about a diamond, we often think about a material whose value comes from its perfection. In my research, however, I am interested in something almost opposite: the tiny imperfections inside diamonds.
These atomic-scale defects can give diamonds new optical and electronic properties, and some of them can serve as quantum systems. The challenge is learning how to control these defects without disturbing the others. This problem becomes particularly important for quantum technologies.
A nitrogen-vacancy (NV) center, for example, is a defect formed when a nitrogen atom and a neighboring vacancy occur in the diamond lattice. NV centers can be used as quantum bits, or qubits, and as highly sensitive sensors of magnetic and electric fields. But creating or modifying one type of defect can also affect other defects nearby.
If we want to build useful devices from diamond, we need ways to control individual defect populations more selectively. Our work, now published in the journal Diamond and Related Materials, explored whether ultraviolet laser pulses could provide that control. I used a single-crystal chemical vapor deposition (CVD) diamond and irradiated localized regions of the crystal with 266-nanometer ultraviolet laser pulses.
The pulses were only a few nanoseconds long, allowing the laser energy to be delivered to a very small region of the material. Rather than heating the entire diamond, the goal was to investigate whether this localized optical excitation could modify particular defects within the lattice. Before exposing the diamond to the laser, we first needed to understand what was already present.
This became an important part of the study because it is difficult to claim that a defect was created by a laser if it was already present in the starting material. We therefore characterized the pristine diamond using confocal photoluminescence spectroscopy, ultraviolet-visible absorption spectroscopy and Fourier-transform infrared spectroscopy. The confocal measurements established the initial optical defect landscape, while the absorption and infrared measurements provided additional information about the optical transparency and impurity content of the starting crystal.
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