High-Energy Single-Frequency Millisecond 1336.630-nm Nd:LGGG Amplifier (April 2017)

We demonstrate a high-energy, single-frequency, and millisecond (ms) 1336.630-nm amplifier with high beam quality and narrow-linewidth simultaneously based on the Nd
³⁺
:(Lu
_x
Gd
_1-x
)
₃
Ga
₅
O
₁₂
(Nd:LGGG) disordered crystal for the first time. The amplifier system consists of a polarized single-frequency 1336.630-nm LD oscillator, two-stage Raman fiber preamplifier, and four-stage Nd:LGGG main amplifier. The seed laser pulse energy is amplified up to a record high pulse energy of 2.05 J at a repetition rate of 5 Hz and a pulse duration of 1 ms with linewidth as narrower as 0.5 pm. The beam quality factor is
${\rm{M}}^{2}\,= \,1.46$
. The wavelength of the single-frequency amplifier can be tuned from 1336.600 to 1336.660 nm. All results indicate that the Nd:LGGG is high performance 1.3-μm laser amplification medium, especially for generating the specific wavelength at 1336.630 nm. Moreover, such laser source with the specific wavelength at 1336.630 nm is promising for the development of a high accuracy
²⁷
Al
⁺
ion optical clock.