Diode-pumped continuous wave tunable and graphene Q-switched Tm:LSO lasers

Abstract

We have investigated the lasing characteristics of Tm:LSO crystal in three operation regimes: continuous wave (CW), wavelength tunable and passive Q-switching based on graphene. In CW regime, a maximum output power of 0.65 W at 2054.9 nm with a slope efficiency of 21% was achieved. With a quartz plate, a broad wavelength tunable range of 145 nm was obtained, corresponding to a FWHM of 100 nm. By using a graphene saturable absorber mirror, the passively Q-switched Tm:LSO laser produced pulses with duration of 7.8 μs at 2030.8 nm under a repetition rate of 7.6 kHz, corresponding to pulse energy of 14.0 μJ.

A passively Q-switched Ho:YVO4 Laser at 2.05 μm with Graphene Saturable Absorber

“…In 2013, T.L. Feng et al proved the graphene as SA in a Tm:LSO laser, acquired the maximum pulse energy of 14.0 µJ and the shortest pulse duration of 7.8 µs [17]. In 2014, Z. Cui et al used graphene to obtain a PQS Ho:LuAG laser with the maximum output power of 0.37 W with a pulse width of 784.7 ns [18].…”

Tm:KLu(WO_4)_2 microchip laser Q-switched by a graphene-based saturable absorber

“…Bulk Nd-, Yb-and Er-lasers Q-switched with graphene were intensively studied during the last decade; however, only few implementations of graphene SA in 2 μm bulk lasers are known. These include Tm:YAG with double-layer graphene on SiC [17], and Tm:CLNGG and Tm:LSO lasers with graphene layer deposited on Cu as a SA mirror [18,19]. In these reports, μs-long pulse durations were achieved at relatively low output power, see summary of output characteristics in Table 1.…”

Dual-loss-modulated passively Q-switched Tm:LuAG laser with multi-walled carbon nanotube and monolayer graphene

“…Recently, the allotropes of carbon, graphene and carbon nanotubes (CNTs) gained their popularity in passively Q-switched lasers at 2 μm for their diverse advantages, e.g., large optical absorption, easy fabrication, low cost, as well as broadband absorption [8,9]. Based on these two kinds of SAs, passively Q-switched 2 μm lasers were actively investigated by several research groups [10][11][12][13][14]. However, most of the pulse durations obtained from graphene or CNTs Q-switched solid-state bulk 2 μm lasers were beyond 500 ns [10][11][12][13].…”

“…Based on these two kinds of SAs, passively Q-switched 2 μm lasers were actively investigated by several research groups [10][11][12][13][14]. However, most of the pulse durations obtained from graphene or CNTs Q-switched solid-state bulk 2 μm lasers were beyond 500 ns [10][11][12][13]. For CNTs, the increase in the layer numbers can enhance the mechanical strength, the thermal stability as well as the laser damage threshold, which are of great importance for short-pulse operation [15], while for graphene, the increase in the layer numbers may increase the nonsaturable loss, which would decrease the modulation depth [16].…”