SESAM (Semiconductor Saturable Absorber Mirror) passive mode-locking laser

The invention relates to a SESAM (Semiconductor Saturable Absorber Mirror) passive mode-locking laser. The mode-locking laser comprises a single tube semiconductor laser, a self-focusing lens, a laser crystal, a plano-concave reflector a, a plano-concave reflector b, a plane reflector, an output lens and an SESAM saturated absorption lens and is based on a picosecond laser technology; the mode locking requires that the energy flux density entering the SESAM saturated absorption lens is high enough; a resonant cavity is symmetrically arranged in a Z-shaped manner, optical elements of the resonant cavity are independent, the layout of the optical elements is compact, and therefore the laser is simple in structure and is small in size; the resonant cavity selects SESAM as a mode-locking component, the SESAM is the combination of a semiconductor saturable absorber and a reflector; the laser is very simple and has the advantages of self-starting property, good stability and the like; and the resonant cavity is simple and compact, and a stable mode-locking pulse is obtained.