Compact Nd:YAG laser operating at 1.06, 1.32, and 1.44 μm

摘要

The aim of this study was design and construction of a Nd:YAG laser system allowing laser generation in the near-infrared region at three separate switchable wavelengths 1.06, 1.32, or 1.44 μm. This integrated multi-wavelength laser system can be useful for application especially in medicine and spectroscopy. We used 1.1 at. % Nd/Y doped Nd:YAG active medium 4 × 102 mm in dimensions with anti-reflection coated faces for 1.06, 1.32, and 1.44 μm. The laser crystal was placed along Xe flashlamp into the diffuse pump cavity (the pump pulse duration was 800 us FWHM). The laser system was formed by six mirrors including one output coupler, three rear mirrors, and two dichroic mirrors. These dichroic mirrors were specially designed and their characteristics were as follow: HR/T @ 1440/1320 and 1064 nm and HR/T @ 1320/1064 nm. The output coupler reflectivity was 17 %, 80 %, and 82 %, for 1.06, 1.32, and 1.44 μm wavelengths, respectively. Particular laser Nd:YAG line selection was realized by adequate shutters. The output laser characteristics in terms of output energy, spatial beam structure, and temporal profile were recorded. For 62 J pumping energy, the obtained output energies were 0.80 J, 0.45 J, and 0.19 J, for 1.06, 1.32, and 1.44 μm wavelengths, respectively. Specific absorption properties of the designed wavelengths in water and water vapor together with the sufficient reached energy predetermine this compact Nd:YAG laser system for utilization in medical and industry applications.