It shows typical features of the Q-switching operation.
Chen et al., "Mechanically exfoliated black phosphorus as a new saturable absorber for both Q-switching and mode-locking laser operation," Optics Express, vol.
As the absorbed pump power was increased to 9.5 W, Q-switching operation was initiated.
Compared with the CW spectrum, there is a blue shift in Q-switching pulse spectrum, which could be attributed to the larger loss (18%) of the SESAM, measured at the wavelength of 2717 nm.
In Q-switching operation, the laser emitted stable Q-switched pulses with an average output power of 223 mW, a pulse energy of 1.7 [micro]J, a pulse width of 350 ns, and a repetition rate of 130.6 kHz at 2709.3 nm.
In both cases, the Q-switching
device emits rapid bursts of the laser beam to the treatment site.
In order to achieve Q-switching operation, we replaced the highly reflective mirror with BP SAM.
By precisely adjusting the longitudinal and transverse position of BP SAM, self-started Q-switching operation was observed on a digital oscilloscope at the launched pump power of 16.6 W Figure 4(a) shows three typical Q-switched pulse trains recorded at the output power of 363 mW, 505 mW, and 615 mW, respectively.
In this paper, we also focus on the capacity of BP in ultra-short pulse generation and demonstrate a submicrosecond Q-switching pulse with a compact Er-doped all-fiber ring laser.
In this condition, we cannot obtain Q-switching operation state no matter how we adjust pump power and apply stress on fiber (correspondingly changing fiber birefringence to control the polarization rate of light in cavity).
To verify the Q-switching performance of LGS at the 2.79 [micro]m wavelength, a Cr,Er:YSGG crystal was employed as a gain medium to form a Q-switched laser system.
In summary, LGS has good prospects for EO Q-switching crystals operating at near-IR and mid-IR region and LGS-based Q-switched lasers will drive the development of short pulses and high-energy laser devices.