Laser Emission Of Nd Research Articles

Selection of π- and σ-polarization laser emission in Nd:Lu0.5Y0.5VO4 mixed crystal

Polarized fluorescence spectra and laser emission of π- and σ-polarization were investigated with a Nd: Lu0.5Y0.5VO4 mixed crystal. A polarizing beam splitting cube was proposed for active selection of oscillating polarization. At a pump power of 12.4W, 5.72W single wavelength laser at 1065.1nm and 3.55W dual-wavelength laser at 1064.9 and 1067.3nm were obtained for π- and σ-polarization, respectively. The wavelength at 1341nm for both polarization output were also studied. The broader fluorescence spectra with σ-polarization will be excellent in ultra-short pulses production.

Efficient laser operation at 1.06 μm in co-doped Lu3+, Nd3+:GdCa4O(BO3)3 single crystal

Efficient laser emission at 1.06μm was obtained from a diode-laser quasi-continuous wave pumped Nd0.04Gd0.86Lu0.10Ca4O(BO3)3 (Nd:GdLuCOB) single crystal. An uncoated, 6.0-mm long, ZX-cut Nd:GdLuCOB medium yielded laser pulses with 1.76W peak power for absorbed pump pulses of 5.49W peak power, corresponding to an overall optical-to-optical efficiency ηoa=0.32; the slope efficiency was ηsa=0.44. Comparison is made with an uncoated XY-cut Nd:GdCOB medium (4.0-at.% Nd doping and 6.8-mm length) from which laser pulses with 1.74W peak power (at optical efficiency ηoa=0.25) and 0.31 slope efficiency were obtained. The improvements in laser emission of Nd:GdLuCOB at the fundamental wavelength are important for future self-frequency doubling in ZX principal plane of this crystal.

Efficient 1061 and 1329 nm laser emission of Nd:CNGG lasers under 885 nm diode pumping into the emitting level

We report an efficiency Nd:CNGG laser operating at 1061 and 1329 nm, respectively, direct pumped by a diode laser at 885 nm for the first time to our knowledge. The maximum outputs of 4.5 and 2.9 W, at 1061 and 1329 nm, respectively, are obtained in a 6-mm-thick 0.5 at % Nd:CNGG crystal with 13.5 W of absorbed pump power at 885 nm, leading to a high slope efficiency with respect to the absorbed pump power of 32.2 and 22.1%. Under traditional pumping at 808 nm, the maximum outputs of 3.9 and 2.7 W, at 1061 and 1329 nm, respectively, are obtained with 15.4 W of absorbed pump power, corresponding to the slope efficiency with respect to the absorbed pump power of 25.2 and 17.9%.

Efficient 1047 nm CW laser emission of Nd:YLF under direct pumping into the emitting level

We demonstrate a 1047 nm Nd:LiYF 4 (Nd:YLF) laser by directly pumping into the upper lasing level with a tunable Ti:Sapphire laser. The results obtained for direct upper laser level pumping at 863, 872 and 880 nm of Nd:YLF were compared with traditional 806 nm pump band excitation. Highly efficient 1047 nm continuous-wave (CW) laser emission under direct pumping at 880 nm in an 8 mm thick, 1.0 at.% Nd:YLF crystal is obtained. The slope efficiency is improved from 55.6% for traditional pumping at 806 nm to 76.3% for direct pumping at 880 nm.

All solid-state continuous-wave Nd:YAG laser at 1319 and 659.5 nm under direct 885 nm pumping

The continuous-wave high efficiency laser emission of Nd:YAG at the fundamental wavelength of 1319 nm and its 659.5-nm second harmonic obtained by intracavity frequency doubling with an LBO nonlinear crystal is investigated under pumping by diode laser at 885 nm (on the 4 F 3/2 → 4 I 13/2 transition). An end-pumped Nd:YAG crystal yielded 9.1 W at 1319 nm of continuous-wave output power for 18.2 W of absorbed pump power. The slope efficiency with respect to the absorbed pump power is 0.55. Furthermore, 5.2 W 659.5 nm red light is acquired by frequency doubling, resulting in an optical-to-optical efficiency with respect to the absorbed pump power of 0.286. Comparative results obtained for the pump with diode laser at 808 nm (on the 4 F 5/2 → 4 I 13/2 transition) are given in order to prove the advantages of the 885 nm wavelength pumping.

Highly efficient continuous-wave intracavity frequency-doubled Nd:YVO4-LBO laser at 457 nm under diode pumping into the emitting level 4F3/2

The continuous-wave high efficiency laser emission of Nd:YVO4 at the fundamental wavelength of 914 nm and its 457 nm second harmonic obtained by intracavity frequency doubling with an LBO nonlinear crystal is investigated under pumping by diode laser at 880 nm into emitting level 4F3/2. 6.5 W at 457 nm with M2=1.8 was obtained from a 5-mm-thick 0.4 at.% Nd:YVO4 laser medium and a 15-mm-long LBO nonlinear crystal in a Z-type cavity for 18.6 W absorbed pump power. An optical-to-optical efficiency with respect to the absorbed pump power was 0.35. Comparative results obtained for the pump with diode laser at 808 nm, into the highly-absorbing level 4F5/2, are given in order to prove the advantages of the 880 nm wavelength pumping.

Laser emission in Nd:YVO4 channel waveguides at 1064 nm

In this work, we report 1064 nm laser emission in Nd:YVO4 channel waveguides fabricated by carbon implantation. Typical threshold pump powers (∼808 nm) were ≥45 mW. Maximum conversion efficiency was 11.5% (29.6% slope efficiency), and up to 9 mW of signal was delivered. Sample lengths of 4 mm were sufficient to completely absorb the pump power. The special spectral characteristics of this material such as broad absorption band and superior cross sections compared to the YAG crystal makes it suitable for developing compact sources to be integrated in optoelectronic devices.

On the origin of bichromatic laser emission in Nd^3+-doped fluoride glasses

In this work we present a detailed study about the influence of the host matrix in the spectroscopic and laser properties of Nd3+ in three different fluoride glasses. Site-selective time-resolved techniques have been used to investigate the crystal field changes felt by the Nd3+ ion as a consequence of glass inhomogeneity. Stimulated emission experiments performed under selective wavelength laser pumping show the existence of bichromatic emission from two distinguishable site distributions for Nd3+ in fluoride glasses. This result can be explained by the moderate inter-site energy transfer among Nd3+ ions found in these systems.

Laser operation at high repetition rate of 100 kHz in Nd:GdVO4 under 879 nm diode-laser pumping

Highly efficient continuous-wave and acousto-optically Q-switched laser emission in Nd:GdVO4 crystal, end-pumped at 879 nm into the laser emitting level, are reported. A maximum cw output power of 13.3 W is obtained, corresponding to the slope efficiency of 74.6% in absorbed power; an average output power of 12.1 W, a pulse width of 20.3 ns and a peak power of about 6 kW are reached at 100 kHz in A-O Q-switched operation.

Diode pumped Nd:GSAG and Nd:YGG laser at 942 and 935 nm

Two new Nd 3+ doped crystals show laser activity between the 4F 3/2 and 4I 9/2 levels. Diode pumped emission of Nd:GSAG at 942 nm wavelength with 950 mW output power and 14% optical to optical efficiency as well as laser emission of Nd:YGG at 935 nm with 700 mW output power and 11% efficiency have been obtained. These wavelengths are useful for water vapour absorption measurements.

Highly efficient, 084 slope efficiency, 901 nm, quasi-two-level laser emission of Nd in strontium lanthanum aluminate

The possibility of using direct pumping into the emitting level of the Nd3+ ion in magnesium-compensated strontium lanthanum aluminate (Sr(1-x)La(x-y)Nd(y)Mg(x)Al(12-x)O19) to improve 900 nm 4F(3/2) --> 4I(9/2) laser emission is discussed. Selection of the composition parameters x and y for optimization of laser emission and reduction of heat generation is based on the spectroscopic and crystal growth characteristics. Pumping in the 865.5 nm absorption band 4I(9/2)(Z1) --> 4F(3/2)(R1) transforms the laser process into a quasi-two-level scheme of very low (below 4%) quantum defects. A very high slope efficiency (over 84%) for 901 nm continuous-wave laser emission is demonstrated with Ti:sapphire laser pumping in this band for a crystal with x = 0.4 and y = 0.05.

High-power continuous-wave intracavity frequency-doubled Nd:GdVO/sub 4/-LBO laser under diode pumping into the emitting level

The continuous-wave high power laser emission of Nd:GdVO/sub 4/ at the fundamental wavelength of 1.06 /spl mu/m and its 531-nm second harmonic obtained by intracavity frequency doubling with an LBO nonlinear crystal is investigated under pumping by diode laser at 808 nm (on the /sup 4/I/sub 9/2//spl rarr//sup 4/F/sub 5/2/ transition) and 879 nm (on the /sup 4/I/sub 9/2//spl rarr//sup 4/F/sub 3/2/ transition). It is shown that, in spite of a lower absorption at 879 nm, the infrared emission is comparable under these two wavelengths of pump. The green emission performances were, however, improved by the 879 nm pump: 5.1 W at 531 nm with M/sup 2/=1.46 and 0.31 overall optical-to-optical efficiency was obtained from a 3-mm-thick 1-at.% Nd:GdVO/sub 4/ laser medium and a 10-mm-long LBO nonlinear crystal in a Z-type cavity for 16.5 W pump power. In similar conditions, the maximum green power for the 808 nm pump was 4.4 W, with 0.26 overall optical-to-optical efficiency and M/sup 2/=3.40 beam quality; at this pump wavelength the green emission shows evident saturation for pump power in excess of 9.9 W. This behavior is connected with the enhanced heat generation under 809-nm pumping, as evidenced by the increased thermal lensing of the fundamental emission. A careful alignment of the laser enables emission almost free of chaotic intensity fluctuations.

1.34-μm efficient laser emission in highly-doped Nd:YAG under 885-nm diode pumping

We report on 1.34-mum laser emission in Nd:YAG under diode pumping at 885 nm, directly into the 4F3/2 emitting level. 3.8 W of output power with 0.26 overall optical-to-optical efficiency was recorded from a 2.5- at.% Nd:YAG single-crystal. Comparative results obtained by classical pumping at 809 nm, in the highly absorbing 4F5/2 level, are presented, showing the advantage of the direct pumping. The influence of lasing wavelength and Nd concentration on the thermal effects induced by optical pumping into the active component is discussed.

Excited-state absorption and 1064-nm end-pumped laser emission of Nd:YVO4 single-crystal fiber grown by laser-heated pedestal growth.

We present an investigation of the excited-state absorption and laser emission of a 1.0-at. %-Nd3+-doped YVO4 single-crystal fiber grown by the low-cost and versatile laser-heated pedestal growth technique. Efficient laser emission at 1064 nm was achieved when the fiber was pumped, in an end-pump cavity, by a Ti:sapphire laser at 808 nm. A continuous-wave threshold of 10 mW was observed with an efficiency of 42% with respect to the absorbed pump power and the maximum output power of 200 mW. These results are excellent when compared with those of a commercial bulk crystal adapted to the same cavity (48% efficiency, 250-mW maximum output power). Thus the fibers are characterized as strong candidates for the construction of compact lasers that can also be pumped by low-cost diode lasers.

Quasi-three-level 946 nm CW laser emission of Nd:YAG under direct pumping at 885 nm into the emitting level

The possibility to enhance the laser emission characteristics and to reduce the heat generation for the 946 nm Nd:YAG laser by direct pumping into the emitting level is discussed. Improved laser characteristics are demonstrated with a 1 at.% Nd:YAG component under 885 nm pumping into the thermally activated transitions Z 2→R 1 and Z 3→R 2 of the 4 I 9/2→ 4 F 3/2 absorption.

Highly efficient laser emission in concentrated Nd:YVO 4 components under direct pumping into the emitting level

Reduction of the quantum defect in four-level lasers by pumping directly into the emitting level can improve laser emission parameters and diminish heat generation. Using concentrated components can compensate reduced absorption in the emitting level of Nd laser materials. These benefits are demonstrated by stable and highly efficient 1064 nm continuous-wave laser emission of Nd:YVO 4 components of 1, 2 and 3 at.% Nd under end-pumping into 4 F 3/2 at 878.6 nm with a Ti:sapphire laser.

Site-effects on the laser emission of Nd 3+ ions in a new fluoride glass

Site-selective spectroscopy and stimulated emission experiments were performed in the 4 F 3/2 → 4 I 11/2 laser transition of Nd 3+ in a new fluoride glass with composition (in mol%) 30BaF 2–18InF 3–12GaF 3–20ZnF 2–9LuF 3–6ThF 4–4MnF 2–1NdF 3 (BIGaZLuTMn). The experiments show the existence of simultaneous laser emission from two distinguishable subsets of Nd 3+ sites. The stimulated emission outputs are at 1050.2 and 1054.9 nm. The temporal behavior of the laser emission spectra shows wavelength dependence in accordance with the existence of broad Nd 3+ site distributions.