MoTe2-Based Broadband Wavelength Tunable Eye-Safe Pulsed Laser Source at $1.9~\mu$ m

In this letter, molybdenum ditelluride (MoTe
₂
), a new member of the transition metal dichalcogenides family, has been characterized and fabricated as an optical modulator for the development of broadband wavelength tunable laser using a Tm
³⁺
-doped CaYAlO
₄
crystal as a laser gain medium. The maximum average output power reaches 0.75 W with the shortest pulse width of about
$0.69~\mu \text{s}$
and repetition rate of 70.9 kHz, which leads to a pulse energy of about
$10.58~\mu \text{J}$
and peak power of 15.3 W. Keeping the MoTe
₂
optical modulator inside the laser resonator and at the same time introducing an undoped YAG for wavelength tuning, wavelength tunable passively Q-switched laser operation with a wavelength range of about 112 nm has been demonstrated. This letter experimentally verifies the potential of the novel 2D material MoTe
₂
as an optical modulator. At the same time, this letter paves the way toward the realizations of simple and compact wavelength tunable pulsed laser sources based on broadband 2D materials saturable absorbers.