“…At first, saturable absorbing mirrors on semiconductor (SESAMs) were discovered as a promising SAs which could achieve stable mode locked and Q switched pulses [5]. Owing to the mirror alignment issues in SESAMs, many other potential materials emerged as new SAs which included graphene, black phosphorus, transition metal dichalcogenides (TMDs), topology insulators (TIs), organic materials, metals, metal carbides and metal oxides [6][7][8][9][10][11][12][13]. All these SAs could achieve stable mode locked and Q switched lasers.…”