Simultaneous oscillations of twelve wavelengths around 1.3 μm in quasi-CW Nd:YAG laser

In this work, a simple cavity configuration for simultaneous observation of twelve oscillating wavelengths around 1.3 µm in a quasi-CW side pumped Nd:YAG laser is proposed and demonstrated experimentally. The experiment has been studied in free running condition and by placing a position tunable Brewster plate within a linear cavity where new wavelengths viz. 1318.71 nm, 1338.14 nm, 1338.16 nm, 1338.18 nm, 1338.21 nm, 1338.23 nm, 1338.25 nm and 1338.27 nm have been observed. By introducing a Brewster plate within the cavity it is possible to maintain almost equal spectral contributions around 1318 nm and 1338 nm wavelength's regions at the highest as well as lowest pump power levels. The maximum average output power of 20 W and 13.87 W at slope efficiencies of 42.22% and 35.37% are obtained in both conditions respectively. In this work it is also possible to measure the average output powers around 1319 nm and 1338 nm regions simultaneously at different average pump powers. The experimental results indicate the higher and better stability of power contributions of observed oscillating wavelengths around 1.3 µm. The beam quality factor varies from 1.11 to 1.44 with the rise in average pump power simultaneously. The proposed work may enhance the application of 1.3 µm laser in spectroscopic field and tunable laser generation. Moreover, by difference frequency mixing within these closely spaced wavelengths this configuration may also be a good source of coherent THz generation.