Green Er(3+):YLiF(4) upconversion laser at 551nm with Yb(3+) codoping: a novel pumping scheme

We report room-temperature continuous-wave upconversion laser emission on the green transition (4)S(3/2)?(4)I(15/2) in Er(1%), Yb(3%):YLiF(4) at 551nm. Green laser operation was obtained for titanium-sapphire pump wavelengths continuously tunable between 955 and 974.5nm. Codoping with Yb(3+) resulted in a more efficient excitation of the upper laser level by upconversion processes. The maximum green laser output power was 37mW at an incident titanium-sapphire pump power level of 1580mW at 966nm.     

Diode-pumped single-frequency Tm:LiLuF(4) ring laser

We report a room-temperature single-frequency Tm:LiLuF(4) laser with a maximum output power of 120 mW, a slope efficiency of 13%, and a wavelength tunability range from 1875 to 1895 nm. Both frequency and relative intensity noise have been investigated, showing an emission linewidth of ~300 kHz over 1 ms observation time and an intensity noise spectrum limited by quantum noise for Fourier frequencies larger than 5 MHz.     

Diode-pumped 1-W continuous-wave Er:YAG 3-mum laser

We have demonstrated 1.15 W of Gaussianlike (M(2) = 2) cw output at 2.94 mum from a diode laser end-pumped monolithic laser crystal composed of Er-doped yttrium aluminum garnet (YAG) bonded to undoped YAG. The laser was pumped with two polarization-coupled 2.5-W flared laser diodes that provided a 45-mum pump waist with a low N.A. (<0.04) . Output at 2.94 mum was generated with a 34% slope efficiency and a greater-than-unity quantum efficiency.     

Enhanced green upconversion emission of Er(3+) through energy transfer by Dy(3+) under 800 nm femtosecond-laser excitation

Er(3+) green upconversion (UC) emission corresponding to the transition of (4)S(3/2) ((2)H(11/2))-->(4)I(15/2) is enhanced in a Er/Dy-codoped LiNbO(3) crystal compared with Er-doped LiNbO(3) under 800 nm femtosecond-laser excitation at room temperature. The upconversion mechanisms are proposed based on spectral, kinetic, and pump-power dependence analyses. The energy-transfer efficiency from Dy(3+)((4)F(9/2)) to Er(3+)((4)F(7/2)) is 33%, which results in the enhancement of green UC emission. This energy transfer is advantageous for the Er(3+) UC emission sensitized by Dy(3+), especially in a low-phonon-energy host matrix.     

Highly efficient infrared-to-visible energy upconversion in Er(3+):Y(2)O(3)

Very intense green and red emission was observed at room temperature from the (4)S(3/2) and (4)F(9/2) levels of Er(3+):Y(2)O(3). A cw diode laser at 975 nm was used as a pump for resonant sequential excitation of the (4)I(11/2) and (4)F(7/2) levels. The fluorescence was easily visible to the naked eye, even with 27 mW of excitation power. It was found that at 850 mW of cw excitation power the total luminance was 39,000 cd/m(2). This corresponds to ~100 muW of green emission and 270 muW of red emission.     

Diode-pumped Nd:Y_xGd_(1-x)VO_4 crystal continuous-wave laser

The diode-pumped Nd:YxGd1-xVO4 crystal continuous wave (CW) laser operating at 1.06 μm with a simple plane-concave cavity and a "V-shaped" folded cavity for intracavity frequency-doubling have been studied. With the incident pump power of 8 W, an output power (1.06μm) of 3.4 W was achieved, giving an optical conversion efficiency of 42.5%. 884 mW of stable green radiation was generated with the incident pump power of 5.9 W, giving an optical conversion efficiency of 15%.     

Diode-pumped Pr(3+):KY(3)F(10) red laser

We report the first observation to our knowledge of room-temperature continuous-wave laser operation of a Pr(3+):KY(3)F(10) single crystal at 644.5 nm, pumped by a blue GaN laser diode emitting at 446 nm. With a 2.5% transmission output coupler and a nonoptimized optical cavity, an output power of 39 mW was obtained at 644.5 nm with a laser threshold of 125 mW and a differential slope efficiency of 23%.     

Efficient 1 W continuous-wave diode-pumped Er,Yb:YAl3(BO3)4 laser

We report the spectroscopy and high-power continuous-wave (CW) diode-pumped laser operation of Er:Yb:YAl3(BO3) crystal. Absorption and stimulated emission spectra, emission lifetimes, and efficiency of energy transfer from Yb3+ to Er3+ ions were determined. A CW Er:Yb:YAB laser emitting at 1602, 1555, and 1531 nm with output power as high as 1W and slope efficiency up to 35% was demonstrated.     

Efficient continuous-wave self-frequency-doubling green diode-pumped Yb:YAl(3)(BO(3))(4) lasers

Efficient cw self-frequency-doubled green laser output of 160 mW has been obtained from Yb:YAl(3)(BO(3))(4) crystal pumped by 1.4-W incident power from a fiber-coupled 976-nm laser diode. The incident-pump-power-green-output-power conversion efficiency is greater than 11.3%, and the electrical-input-green conversion efficiency is 3.9%. Tunable green output from 513.0 to 545.8 nm is also demonstrated with a quartz birefringent filter.     

Uniform upconversion in high-concentration Er(3+)-doped soda lime silicate and aluminosilicate glasses

Uniform upconversion in erbium-doped silicate glasses is investigated as a function of glass composition, concentration, and fabrication method. Comparisons of upconversion coefficients are made among soda lime silicate and aluminosilicate bulk glasses and soda lime silicate waveguides. Comparisons are also made with studies performed by other researchers. The results indicate that both the composition and the preparation method of the glass affect the value of the upconversion coefficient, with as much as a factor-of-4 variation observed at fixed Er(3+) concentration. Values of the upconversion coefficient are found to be consistent with the F?rster-Dexter microscopic model.     

Diode-pumped passively mode-locked Er,Yb:YAl3(BO3)4 laser at 1.5-1.6 microm

We report the first demonstration to our knowledge of passive mode locking in a diode-pumped Er(3+) and Yb(3+) codoped YAl(3)(BO(3))(4) laser operating in the 1.5-1.6 microm spectral region. Low-loss GaInNAs quantum-well semiconductor saturable absorber mirrors are used for the initiation and stabilization of the ultrashort-pulse generation. Pulses as short as 4.8 ps were generated at 1530 nm with an average output power up to 280 mW for 2 W of absorbed pump power produced by a high-brightness tapered 980 nm laser diode. Passive mode locking has also been demonstrated around 1555 nm with typical average powers of around 100 mW and pulse durations of 5.1 ps.     

Er~(3+)∶YVO_4的频率上转换动力学分析

测量并分析了980nm抽运下Er3+∶YVO4晶体的上转换荧光,建立了描述Er3+离子跃迁的速率方程。通过求解速率方程并拟合1550nm,980nm和550nm的荧光衰减实验曲线,得到了4I13/2+4I13/2→4I15/2+4I9/2,4I11/2+4I11/2→4I15/2+4F7/2的频率上转换系数C22=9.221×10-17cm3s-1,C33=7.545×10-17cm3s-1。通过测量980nm抽运下的550nm荧光衰减谱,得到了4S3/2能级的主要上转换机制是以激发态吸收为主。     

Diode-pumped self-Q-switched single-frequency 946-nm Nd(3+), Cr(4+):YAG microchip laser

A stable low-threshold self-Q-switched diode-pumped 946-nm Nd(3+), Cr(4+):YAG microchip laser operating in single frequency and fundamental transverse mode is reported. The output characteristics of the microchip laser were investigated under cw and pulsed pumping. By combination of the infrared microchip and an external frequency doubler, 473-nm pulses with a conversion efficiency of 18% were achieved.     

Direct diode-pumped continuous-wave near-inf rared tunable laser operation of Cr(4+):forsterite and Cr(4+):Ca(2)GeO(4)

Continuous-wave tunable laser operation of direct diode-pumped Cr(4+):Mg(2)SiO(4) (Cr:forsterite) and Cr(4+):Ca(2)GeO(4) (cunyite) crystal were demonstrated. Diode-pumped Cr:forsterite was tunable over the 1236-1300-nm spectral range. The maximum output of 10 mW was measured at 1260 nm for 640 mW of pump power absorbed by the crystal. Diode-pumped laser operation of cunyite was also demonstrated over the 1390-1475-nm range. Free-running 20-mW output was centered at 1410 nm.     

Competition between green and infrared emission in Er:YLiF4 upconversion lasers

The competition between two laser transitions in Er:YLiF₄ (⁴S_3/2 → ⁴I_15/2 at 551 nm and ⁴S_3/2 → ⁴I_13/2 at 850 nm) is studied using a model based on rate equations. The laser emission is pumped by upconversion at 795 nm; for comparison, we also discuss upconversion pumping by another mechanism, at 970 nm. The conditions that favor laser emission in various regimes on these two transitions are found.     

Diode pumping of a continuous-wave Pr3+-doped LiYF4 laser

We report, for the first time to our knowledge, diode-pumped cw laser oscillation of Pr3+:LiYF4 in the red spectral range. The pump power is provided by a GaN laser diode emitting a maximum output power of 25 mW at a wavelength of approximately 442 nm. The Pr3+ laser emits 1.8 mW of output power at a 639.7-nm wavelength. Threshold pump power and slope efficiency in a nonoptimized setup are determined to be 5.5 mW and 24%, respectively.     

One-color one-beam pumping of Er(3+)-doped ZBLAN glasses for a three-dimensional two-step excitation display

We demonstrate a one-color one-beam pumping method for a three-dimensional two-step excitation fluorescent display with Er(3+) -doped ZBLAN glass. A localized green fluorescent spot is obtained by use of a focused pump-light beam at 979 nm. The quantum efficiency of the two-step excitation fluorescence is investigated in a time-dependent analysis and an experiment with a pulsed pump light.     

VUV-UV-visible luminescence of Nd3+, Er3+ and Tm3+ in LiLuF4 single crystal host

An overlook of absorption and luminescence characteristics of Nd³⁺, Er³⁺ and Tm³⁺ centers in LiLuF₄ single crystal is provided. Single crystal doped with the mentioned RE ions were prepared by micro-pulling-down technique in the form of few cm long rods with the diameter of about 2 mm. Excitation and emission spectra and fast decay kinetics in VUV spectral region were measured at SUPERLUMI station at synchrotron DESY, Hamburg and characterization was further completed in UV-visible region at conventional spectrophotometers. Observed absorption and emission peaks are ascribed to the 5d–4f and 4f–4f optical transitions in the doped rare earth ions. Concentration dependence of the decay kinetics is discussed.     

Diode-pumped continuous-wave and femtosecond laser operations of a heterocomposite crystal Yb3+: SrY4(SiO4)3O parallel Y2Al5O12

We report cw and femtosecond laser operations under diode pumping of a diffusion-bonding heterocomposite Yb-doped crystal: Yb3+:SrY4(SiO4)3O parallel Y2Al5O12(YAG paralell SYS:Yb). To show the advantages of this heterocomposite crystal over classical Yb:SYS crystal, we first investigate the high-power cw regime. A cw power of 4.3 W is demonstrated. The femtosecond regime is also investigated, and 1-W-average-power, 130-fs pulses at 1070 nm are produced, which represents, to our knowledge, the first demonstration of an Yb-doped heterocomposite mode-locked laser.