Diode-side-pumped Nd:YLF laser emitting at 1313 nm based on DBMC technology

Abstract

Efficient lasers operating in the 1.3 μm band are of interest in the health industry for frequency conversion to the visible spectral region and for Raman shifting to the eye-safe 1.5 μm region. In this work, we demonstrate for the first time, to our knowledge, a side-pumped Nd:YLiF(4) laser emitting at 1.3 μm. An output power of up to 14.9 W was obtained at 1313 nm with 54 W of absorbed pump power, representing 27.7% optical efficiency and a slope efficiency of 45%.

Power scaling of a side-pumped Nd:YLF laser based on DBMC technology

“…This occurs because beyond 80 W of pump power (40 A of diode current) the diodes suffer a spectral broadening as pointed out above and in Ref. [17].…”

“…The spectral broadening of the diodes increases the penetration depth, resulting in a poorer overlap between the fundamental mode of the laser oscillation and the pump beam. Therefore, the laser output power and, consequently, its efficiency are decreased [17]. This effect is especially detrimental to the 797 nm emitting diode, because the Nd:YLF absorption peak at this wavelength is 21 % narrower than the 792 nm absorption peak.…”

“…M 2 values of 1.15 and 1.07 were obtained in the horizontal and vertical directions, respectively. The excellent beam quality demonstrates that even at very high intracavity powers, multimode oscillation is avoided by the DBMC technique, which is equivalent to a soft aperture for higher modes [17].…”

“…Both diode beams were focused into the two crystals by a f = 20 mm spherical lenses, resulting in spot sizes of approximately 4 mm width and 0.1 mm height. At 40 A of drive current, the diodes showed a spectral emission width of 2 nm FWHM, which increased at higher currents by 26 % [17]. After the focusing optics and Fresnel reflections at the uncoated pump facets, about 88.5 % of the pump power was effectively absorbed by the slabs.…”

High average power Q-switched 1314 nm two-crystal Nd:YLF laser

“…Recent 1.3 µm Nd:YLF work by other groups based on side-pumped setups delivered CW powers of up to 14.9 W [15] and for actively Q-switched Nd:YLF pumped at 796 nm average powers of up to 12.3 W (from 180 W of pump power) with corresponding pulse energies of 3.8 mJ [16]. Here we demonstrate high-power 1314 nm operation of a diode end-pumped Nd:YLF laser in both CW and actively Q-switched modes.…”