Magneto-Optical Modulation of Bismuth-Doped Rare Earth Iron Garnet in a 1342 nm Resonator

Although bismuth-doped rare earth iron garnet (BIG) thick films are extensively utilized in optical isolators, magneto-optical switches, and non-reciprocal optical devices due to their exceptionally high Faraday rotation angle, broad spectral response, and remarkable thermal stability, there remains a notable lack of research dedicated to the application of BIG for magneto-optical modulation within laser resonators. In this study, 340 μm thick BIG films are randomly positioned within the resonant cavity of a Nd:YVO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> laser at 1342 nm. The saturation magnetic field required for the BIG is only 80 mT. In the absence of an external magnetic field, no laser output is observed. However, when a saturated magnetic field is applied, the laser generates output instantaneously, achieving an output power of up to 485 mW under a pump power of 2987 mW. The experimental results demonstrate that the presence or absence of the output laser can be effectively controlled by adjusting the state of the magnetic field, thereby achieving magneto-optical modulation of the laser. This research not only expands the functional capabilities of BIG thick films, but also provides a novel and efficient intracavity modulation scheme for all-solid-state laser systems. This advancement is anticipated to have significant implications in laser communication, precision processing, quantum optics and other fields.