Diode-pumped 2 (mu)m vibronic (Tm~(3+), Yb~(3+)): KLu(WO_(4))_(2) laser

摘要

We report on laser operation in a (6 at. percent Tm, 5 at. percent Yb):KLu(WO_(4))_(2) codoped crystal. The vibrational frequencies of KLu(WO_(4))_(2) are coupled to the electronic transitions of Tm~(3+) at 1946 nm, creating virtual final laser levels at higher energy than the ground level ~(3)H_(6) of Tm~(3+). The longest recorded laser wavelength was 2039 nm, which is longer than permitted by a pure electronic transition in Tm~(3+) ions in KLu(WO_(4))_(2). We show that every laser wavelength can be explained with the electron-phonon coupling effect, where the vibration frequencies were determined through Raman spectroscopy.