Magnetically Controllable Random Lasers

Abstract Toward practical applications of random lasers, controllability is a key factor. Here, magnetically controllable random lasers (MCRLs) are designed, fabricated, and demonstrated. Under a prescribed magnetic field, the MCRLs composed of stilbene 420 laser dye, TiO₂ nanoparticles, and Fe₃O₄ nanoparticles possess magnetic controllability and switchability with good responsivity and durability. The applied magnetic field can be used to manipulate the distribution of Fe₃O₄ nanoparticles, which in turn alters the formation of the coherent loops and the properties of laser action. The MCRLs developed here can serve as magneto‐optics prototypes for several potential applications, such as biomedicine and optical communications.