Graphitic C_3N_4 as a new saturable absorber for the mid-infrared spectral range

Abstract

The saturable absorption properties of few-layer graphitic carbon nitride (g-C₃N₄) nanosheets near 3 μm were investigated. A stable Q-switched Er:Lu₂O₃ laser at 2.84 μm was realized by using a home-made g-C₃N₄ saturable absorber (SA), generating a pulse duration of 351 ns and an average output power of 1.09 W at a repetition rate of 99 kHz, corresponding to a pulse energy of 11.1 μJ. Our result indicates a great potential of g-C₃N₄ as a new SA in the 3 μm wavelength range.

High Power and Short Pulse Width Operation of Passively Q-Switched Er:Lu2O3 Ceramic Laser at 2.7 μm

“…The Er:Lu 2 O 3 ceramic laser in present work provides similar pulse energy and average output power to the crystal laser, but higher pulse peak power and five times decrease in pulse duration [21][22][23]29]. Compared to the earlier reported PSQ Er:Lu 2 O 3 ceramic laser at 2.7 µm, the average output power and slope efficiency in the present work have increased by nearly an order of magnitude [29].…”

“…Under an absorbed pump power of 9.4 W, the pulse energy was found to be~9.8 µJ and corresponds to a peak power of 0.14 kW. To the best of our knowledge, this is the highest peak power reported for the Q-switched Er:Lu 2 O 3 laser [23]. The typical pulse profile and the corresponding pulse train for the maximum output power is shown in Figure 5.…”

“…Passively Q-switched approaches offer advantages over the active ones in terms of simplicity, compactness and they have no need of extra electric devices. A variety of saturable absorbers (SAs), such as graphene, black phosphorus (BP), MoS 2 , ReS 2 , graphitic carbon nitride (g-C 3 N 4 ), Bi 2 Te 3 , have so far been used for Q-switching of~3-µm lasers [17][18][19][20][21][22][23]. Up to watt-level outputs at 2.84 µm have been demonstrated using Er:Lu 2 O 3 crystal, generating pulses of~350 ns durations and~100 kHz repetition rates [21][22][23].…”

“…A variety of saturable absorbers (SAs), such as graphene, black phosphorus (BP), MoS 2 , ReS 2 , graphitic carbon nitride (g-C 3 N 4 ), Bi 2 Te 3 , have so far been used for Q-switching of~3-µm lasers [17][18][19][20][21][22][23]. Up to watt-level outputs at 2.84 µm have been demonstrated using Er:Lu 2 O 3 crystal, generating pulses of~350 ns durations and~100 kHz repetition rates [21][22][23]. Compared with the newly developed two-dimensional (2D) materials-based SAs, the semiconductor saturable absorber mirror (SESAM) has many advantages since the key parameters, e.g., the absorption recovery time and the modulation depth, can be tailored in a wide range [24].…”

Er-doped all-fiber laser mode-locked by graphitic carbon nitride nanosheets

“…In 2016, nonlinear optical effects of 2D-like C-N polymer nanosheets were investigated, and the 2D-like CN polymer was firstly used as an SA in an allnormal dispersion Yb-doped mode-locked fiber laser at 1.06 μm [17] . In 2017, SAs based on g-C 3 N 4 nanosheets attracted more attention, with which a Q-switched Nd:LuLiF 4 solid laser, a Q-switched Er:Lu 2 O 3 solid laser, and a Q-switched Ho,Pr:LLF solid laser were demonstrated at 1.3, 2.84, and 2.95 μm, respectively [18][19][20] . For convenience of comparison, Table 1 gives a summary of pulsed lasers using g-C 3 N 4 as SAs for optical modulators.…”