Carbon nanotube and graphene saturable absorbers: A new generic mode-locking technology?

Passive mode-locking of laser by utilizing a suitable saturable absorber is a well-known technique for ultrafast pulse generation. Semiconductor-based saturable absorbers such as SESAMs have revolutionized femtosecond laser technology, providing a robust and ultrafast nonlinear optical switching mechanism which enabled practical applications for ultrafast lasers [1]. SESAMs, however, provide a spectrally limited nonlinearity and often require sophisticated manufacturing technology with additional post-treatments to reduce response time for femtosecond operation [2].