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Nationwide College of Singapore (NUS) physicists have developed a technique utilizing a targeted beam of helium ions to create arrays of defects in hexagonal boron nitride (hBN) that may probably be used for magnetic sensing functions.

Hexagonal boron nitride (hBN) is a two-dimensional (2D) materials comprising of boron and nitrogen atoms organized in a hexagonal lattice construction. It reveals distinctive properties for functions in quantum sensing. Many varieties of defects have been found in hBN and certainly one of them, the negatively charged boron emptiness (V_B^–), is of specific curiosity because it possesses spin properties that make it precious for quantum sensing functions.

On this examine, a beam of excessive power helium ions produced on the accelerator facility on the Heart for Ion Beam Functions (CIBA) within the Division of Physics, NUS was used to irradiate flakes of hBN to generate V_B^– optical facilities. The power to focus the ion beam to nano-sized spots and to spatially scan the beam permits for patterned arrays of optical emitters to be fabricated with excessive precision.

The work is the results of a collaboration between a analysis staff led by Affiliate Professor Andrew Bettiol and the staff led by Affiliate Professor Goki Eda, each from the Division of Physics, NUS. The V_B^– optical defect middle which, was produced via the experiments run by the analysis staff, exhibits some fascinating properties when it’s uncovered to microwave power. This examine was revealed within the journal Superior Optical Supplies.

A spectroscopic approach often known as Optically Detected Magnetic Resonance (ODMR) was used to sense tiny magnetic fields within the experiments. This system combines the rules of magnetic resonance and optical spectroscopy to review the properties of paramagnetic supplies and their interplay with electromagnetic radiation.

First, a inexperienced laser is used to excite the V_B^– defect middle in order that it emits gentle at a wavelength of round 810 nm, which is within the close to infra-red a part of the electromagnetic spectrum. A copper antenna is then used to generate a selected microwave frequency close to the hBN pattern. This microwave power initializes the defect right into a spin state that ends in the discount within the gentle depth emitted by the defect. The microwave frequency is tuned till a drop in gentle depth is detected. This occurred at roughly 3.48 GHz, the place a double dip within the photoluminescence depth was noticed. As soon as the microwave resonance frequency is discovered, the sensor is prepared to be used to detect magnetic fields.

Prof Bettiol stated, “By utilizing this distinctive property exhibited by hBN, a tiny magnetic discipline that generally happens in organic methods or in magnetic supplies will shift the resonant frequency and this may trigger the sunshine emission from the sensor to be restored. The sunshine emission from the V_B^– optical defect middle gives a method of optically detecting the native magnetic discipline.”

Prof Eda added, “hBN is a flexible materials that may be readily built-in into on-chip units. Our demonstration to create spin defects in hBN with excessive precision is a crucial step in direction of realizing on-chip magnetic sensors.”