A stable fiber laser operating at appro ximately 976 n m peak power at a 280 ns and 1.9 W pump was used as a pumping source for an upconversion laser based on an Er 3+ :doped LiLuF4 crystal. A 548 n m wavelength and 320 mW could be achieved. In this study, we used a 976 n m lo w threshold average pump power fiber laser at 8 mW, wh ich can achieve green upconversion laser output at room temperature. Th is system includes a high reflective coating at 552 n m+/-10 n m on the LiLuF4 crystal and a 96% reflective mirror forming a laser cavity fo r the 548 n m laser. Using the laser cavity setup and 976 n m fiber laser pu mp, lo w threshold pump power green erbiu m upconversion lasing was achieved. The two peak wavelengths of 548 n m and 537 n m are observed and the intensity changes by changing the input to 976 n m pu mp power.

Effect of an electrostatic field in an electrode-insulator-superconductor system on the voltage-current characteristics of high Tc ceramics with various composition and different preparation technology has been studied at 77 K.Ceramics of YBaCuO (123) and BiPbSrCaCuO 12223) systems and also ones doped by Ag have been used. Electric field strength has been up to 140 MV/m.

All-fiber 546-nm-wavelength green up-conversion amplified emission using an erbium-doped silica fiber at room temperature is demonstrated. Silica fiber is known for its high phonon energy and high nonradiative relaxation rate that prevents up-conversion lasing. In this study, we design an all-fiber system without using a free-space device to generate amplified emission. We use a 975 nm high power diode pump laser, a 25-m-long double-cladding erbium-doped silica fiber, and two specially designed fiber-type end-face reflectors to generate 270 mW, 546 nm green amplified emission. It was found that the high power density inside the double-cladding fiber makes up-conversion lasing possible by overcoming the population inversion. #