This diploma thesis presents the development, experimental evaluation, operation, and measurement capabilities of a quantum optical magnetometer based on optically pumped potassium atoms operating in a pulsed regime. The system includes a custom-built acousto-optic modulator (AOM), constructed from a quartz cuvette filled with alcohol, excited by a 10,9 MHz ultrasonic transducer that generates standing acoustic waves. The pump laser beam is diffracted on these waves, enabling precise switching of the pump beam and effective separation of the pumping and detection phases, which allows observation of the free induction decay (FID) signal.
Detection is based on measuring the rotation of the polarization of a linearly polarized probe laser, induced by changes in the precession (Larmor) frequency of potassium atoms, which depends on the external magnetic field and is detected by a photodiode polarization detector. The system can detect and distinguish dynamic magnetic phenomena, such as the oscillation of a ferromagnetic pendulum and the rotation of a handheld drill with an off-axis iron screw. Simultaneous detection of both signals confirms the system’s ability to distinguish multiple magnetic sources in real time.
The results demonstrate a high signal-to-noise ratio (\textit{SNR}) and sensitivity in the nanotesla range, confirming that accurate magnetic field measurements are possible even with a simplified setup. The system shows strong potential for further improvements, such as the implementation of magnetic gradiometry.
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