A Q-switched Yb:KGW solid-state laser using topological insulator Bi2Se3 as a saturable absorber was demonstrated experimentally for the first time. The Bi2Se3 saturable absorber was fabricated in a film on a highly reflective mirror. By inserting this into a Yb:KGW laser, the Q-switched operation was obtained. The highest average output power was 439.4 mW and the corresponding repetition rate, pulse width and pulse energy were 166.7 kHz, 1.6 μs and 2.64 μJ, respectively. To our knowledge, this is the highest output power among topological insulator-modulated lasers with topological insulator absorbers.

We present a passively Q-switched Yb:KGW laser based on a transmission-type saturable absorber of topological insulator: Bi2Se3. The saturable absorber is prepared on a 0.17-mm glass substrate and can translate intra-cavity for best performance nearly without influence on the laser mode. At a maximum pump power of 13.7 W, the central wavelength, pulse duration, repetition rate, and pulse energy of Q-switched pulse are 1043 nm, 1.5 μs, 175.4 kHz, 6.39 μJ, respectively. The maximum output power is 1.12 W. To our knowledge, this is the highest average output power from passively Q-switched lasers with topological insulator saturable absorbers.

Self-Q-switching is observed in a bulk Yb:KGdðWO 4 Þ 2 oscillator without any additional modulating elements. The output power reaches 434.4 mW at a pump power of 13.67 W, corresponding to pulse repetition rate of 125 kHz and a pulse duration of 2.5 μs, respectively. The mechanism of self-pulse formation is explained by the re-absorption effect of the Yb 3þ ion in Yb:KGdðWO 4 Þ 2 .

We demonstrate a high-repetition-rate Er-doped all fiber laser with nonlinear-polarization-rotation mode-locking. The highest repetition rate of the laser is 217 MHz. The fiber laser has a very simple and compact structure and can output a stable mode-locking pulse only by using one polarization-dependent isolator and a polarization controller. The pulse width, spectral width and signal-to-noise ratio are measured to be 69 fs, 56 nm and 76 dB respectively.

A saturable absorber of 3.9% modulation depth was prepared on the surface of a fiber clad with single-walled carbon nanotubes (SWCNT) using chemical corrosion method. An all-fiber Er-doped fiber laser was setup with a ring cavity, and was mode-locked successfully by evanescent field mode-locking using prepared saturable absorber of single-walled carbon nanotubes. A 147 fs mode-locking pulse is obtained near 1556 nm with a 3 dB bandwidth of 24 nm. The output power is 21 mW at a pump power of 520 mW, corresponding to a pulse energy of 0.14 nJ with a repetition rate of 150 MHz.