Compact and portable quantum sensor module using diamond NV centers

We developed a compact and portable measuring instrument using diamond NV centers that operates on the USB 3.0 power supply of a laptop computer. Its portability is achieved by the low power consumption of the optics, realized by the diamond corner cube that enhanced the current of the photodiode to 2.1 times higher than that of the planar diamond, and that of the microwave source, reduced by 20 dB, which was realized by a microwave resonator using a λ/4 open stub that strongly magnetically drives the NV center. These results contribute to the social implementation of diamond sensors.