Abstract
We recently reported the observation of upconversion laser action in LiYF4:Nd3+ at 729.6 and 413.0 nm originating from the 2P3/2 level at 26,258 cm–1.1 Here we report on cascade laser action at 729.6 and 1053.0 nm using upconversion pumping with a yellow dye laser at low temperatures (T < 70 K). The upconversion excitation of the 2P3/2 level exhibits an unusual nonlinear dependence on pump power and a delayed buildup time.1 The 2-mm long laser crystal of LiYF4:Nd3+ (1%) had spherically polished faces on which mirror coatings were directly deposited. The mirror reflectivities were high (>98%) at 730 nm and low (~15%) at 1053 nm. When pumped by a 603.6-nm cw dye laser oscillation was observed at 729.6 nm, corresponding to the 2P3/2(1) → (4f5/2, 2H9/2)(3) transition. The ions quickly relax nonradiatively to the 4F3/2 state whose lifetime is 525 µs. The resulting buildup in population brings the 1053.0-nm laser transition [4F3/2(1) → 4F11/2(2)] above threshold. At 20 K the pump threshold for cascade laser operation was obtained with 40 mW of incident dye laser power. Investigations of the laser dynamics showed that the 1053.0-nm laser reaches its threshold ~300 µs after the onset of 729.6-nm laser.
© 1989 Optical Society of America
PDF ArticleMore Like This
F. TONG, R. M. MACFARLANE, and W. LENTH
THKK4 Quantum Electronics and Laser Science Conference (CLEO:FS) 1989
F. Tong, R. M. Macfarlane, W. P. Risk, and Wilfred Lenth
FP1 OSA Annual Meeting (FIO) 1989
T. Sandrock, E. Heumann, G. Huber, V Lupei, B. Bejan, and E. Osiac
ThQ7 International Quantum Electronics Conference (IQEC) 1996