Development of the large scanning mirror using Fe-based metallic glass ribbon

In order to achieve the large scanning angle without mechanical failure during actuation, the micro-mirror structure was fabricated using Fe-based metallic glass (MG) ribbon. High values of mechanical strength and elastic strain limit are desired for the torsion bar for providing high performance of the mirror, including large tilting angle and good stability. MG materials guarantee superior value of elastic strain limit and fracture toughness resulting from its amorphous structure without line defects like dislocations and grain boundaries. We chose Fe-base MG material for mirror actuation according to its good soft magnetic properties and simple structure without any further step of integration of magnetic material. Millimeter-size mirror device was successfully fabricated by laser machining techniques from Fe-based MG ribbon. Extremely large optical tilting angle of exceeding 100° was obtained on activation of the mirror by magnetic force when electrical current of 100 mA was applied. Large tilting angle of the mirror is due to the torsion bar which was fabricated with Fe-based MG material that has large elastic strain limit and high fracture toughness.