Silicon Wafer: a Direct Output Coupler in Tm:YLF Laser

Abstract

We present a high power diode-pumped continuous-wave Tm:YLF (Tm 3+ -doped lithium yttrium fluoride) laser with a piece of silicon wafer as the output coupler (Si-OC laser) directly. Under the pump power of 40 W at 793 nm, a maximum output power of 12.1 W is obtained with a beam quality of 𝑀 2 ≤ 1.55 at 1887 nm, corresponding to an optical-to-optical efficiency of 30.25% and a slope efficiency of 33.21%. To the best of our knowledge, this is the first report on directly utilizing silicon as an output coupler (Si-OC) in the solid Tm:YLF laser system. Due to the intriguing characteristics of silicon, such as negligible absorption in the wavelength region around 2 𝜇m, high damage threshold, low cost and long-pass filter properties, double-side polished monocrystalline silicon wafer is considered as an outstanding candidate output coupler in the high-power laser system 2 𝜇m spectral region, which may dramatically reduce the total manufacturing costs of the 2 𝜇m laser system.

Pressure- and temperature-dependent luminescence from Tm3+ ions doped in GdYTaO4

“…[4][5][6] With the up-conversion mechanism and the down-conversion mechanism, Tm 3+ -doped materials can generate UV emissions by 1 D 2 → 3 H 6 transition, blue emissions by 1 D 2 → 3 F 4 transition, blue-green emissions by 1 G 4 → 3 H 6 transition, red emissions by 1 G 4 → 3 H 4 and 3 F 2,3 → 3 H 6 transitions, NIR emissions by 3 H 4 → 3 H 6 and 3 F 4 → 3 H 6 transitions, making them valuable for applications in optical display, [1,4,6] optical sensing, [1,6] lighting, [1,4,6] biological labeling, [1][2][3]7] quantum efficiency enhancing for solar cells, [2,4,5] fiber optics, and medical surgery. [8] Rare-earth tantalates with LnTaO 4 (Ln = Y, Gd, La, Sc, Lu) stoichiometry are promising host materials for rareearth activator ions, [9][10][11][12] which have high density and hardness values, [9,13,14] high x-ray and UV absorptions, [11][12][13] high chemical and physical stabilities. [9][10][11][12][13][14] Moreover, owing to the low symmetry and strong crystal field of this kind of host, activator ions doped can have a high photoluminescence (PL) efficiency.…”