Efficient diode-pumped Yb : Gd2SiO5 laser

An efficient diode-pumped laser was demonstrated by using an ytterbium-doped laser crystal, Yb:Gd2SiO5 (Yb:GSO), wherein Yb3+ ions exhibit the largest ground-state splitting among all the ytterbium-doped crystals. The Yb:GSO laser can be operated at a low pumping threshold, and the most efficient laser occurs around 1088 nm since the corresponding emission band has the largest emission cross section and the lowest thermal population. A slope efficiency of 75% was demonstrated for a continuous-wave Yb:GSO laser at 1094 nm, and self-pulsed lasers were achieved within the tunable range of 1091-1105 nm, which are the longest laser wavelengths achieved for Yb3+ lasers. (c) 2006 American Institute of Physics.

A new Yb-doped oxyorthosilicate laser crystal: Yb : Gd2SiO5

A new Yb-doped oxyorthosilicate laser crystal, Yb:Gd2SiO5 (Yb:GSO), has been grown by the Czochralski (Cz) method. The crystal structure was determined by means of X-ray diffraction analysis. Room temperature absorption and fluorescence spectra of Yb3+ ions in GSO crystal were measured. Then. spectroscopic parameters of Yb:GSO were calculated and compared with those of another Yb-doped oxyorthosilicate crystal Yb:YSO. Results indicated that Yb:GSO crystal seemed to be a very promising laser gain media in generating ultra-pulses and tunable solid state laser applications. As expected, the output power of 2.72 W at 1089 nm was achieved in Yb:GSO crystal with absorbed power of only 4.22 W at 976 nm, corresponding to the slope efficiency of 71.2% through the preliminary laser experiment. (c) 2005 Elsevier Ltd. All rights reserved.

Investigation of optical properties of Ce3+-doped Gd2SiO5 crystal irradiated by a femtosecond laser

We report on the optical property changes for Ce3+-doped Gd2SiO5 crystal irradiated by a femtosecond (fs) laser. Absorption spectra showed that Ce-related color centers were formed in this crystal after an 800 nm fs laser irradiation. The annealing temperature-dependence of the refractive index and absorption intensity changes have been investigated. Furthermore, a new way of writing overlapped gratings inside the crystal by use of birefringence of fs laser beam in this crystal was proposed. (c) 2005 Elsevier B.V. All rights reserved.

Growth and spectral properties of Gd2SiO5 crystal codoped with Er and Yb

Gd2SiO5 (GSO) single crystal codoped with Yb3+ and Er3+ (Abbr. as Er:Yb:GSO) was successfully grown by the Czochralski (CZ) method for the first time and the spectral characteristics were investigated. The absorption and fluorescence spectra were measured. The emission lifetime of the I-4(13/2)-Er-level was measured to be 5.84ms and the emission cross-section at 1529nm was calculated to be 1.03 x 10(-20) cm(2). The results indicate that Er:Yb:GSO is a potential laser material at similar to 1. 55 mu m wavelength region. (c) 2006 Elsevier B.V. All rights reserved.

Low-threshold and continuously tunable Yb : Gd2SiO5 laser

Yb:Gd2SiO5 (Yb:GSO) exhibits a large fundamental manifold splitting. Its long-wavelength emission band around 1088 nm, which has the largest emission cross section, encounters the lowest reabsorption losses caused by thermal population of the terminal laser level. As a result, low-threshold and tunable continuous-wave Yb:GSO lasers were demonstrated. A slope efficiency up to 86% and a pumping threshold as low as 127 mW were achieved for a continuous-wave Yb:GSO laser at 1092.5 nm under the pump of a high-brightness laser diode. A continuous tunability between 1000 and 1120 nm was realized with an SF14 prism as the intracavity tuning element. (c) 2006 American Institute of Physics.

Blue upconversion luminescence generation in Ce3+: Gd2SiO5 crystals by infrared femtosecond laser irradiation

Blue frequency-upconversion fluorescence emission has been observed in Ce3+-doped Gd2SiO5 single crystals, pumped with 120-fs 800 nm IR laser pulses. The observed fluorescence emission peaks at about 440nm is due to 5d -> 4f transition of Ce3+ ions. The intensity dependence of the blue fluorescence emission on the IR excitation laser power obeys the cubic law, demonstrating three-photon absorption process. Analysis suggested that three-photon simultaneous absorption induced population inversion should be the predominant frequency upconversion mechanism. (c) 2006 Optical Society of America.

Group delay dispersion measurement of Yb : Gd2SiO5, Yb : GdYSiO5 and Yb : LuYSiO5 crystal with white-light interferometry

We report the measured group delay dispersion (GDD) of new crystals Yb:Gd2SiO5 (Yb:GSO), Yb:GdYSiO5 (Yb:GYSO) and Yb:LuYSiO5 (Yb:LYSO) over wavelengths from 1000nm to 1200nm, with a white-light interferometer. Those GDD data should be useful for the dispersion compensation for femtosecond pulse generation in the lasers with these new crystals as the gain media. (C) 2007 Optical Society of America

Investigação de Er3+ nos dois sítios cristalográficos de Gd2SiO5 através da fotoluminescência resolvida no tempo

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Time-resolved spectroscopy studies of Gd2SiO5 : Ce3+ from spherical particles

This paper reports on time-resolved emission and excitation spectra measurement studies of Gd2SiO5:Ce3+ in powder or pellet samples, from spherical particles, in order to assign the Ce3+ ion transitions into two different symmetry sites. Samples were obtained from solid-state reaction of the spherical particles oxides, SiO2 and Gd2O3:Ce3+. From time-resolved spectroscopy measurements Ce3+ ion transitions occupying the two different gadolinium crystallographic sites in Gd2SiO5 were separated and assigned. (C) 2002 Elsevier B.V. B.V. All rights reserved.

Spectroscopic characteristics of Er3+ in the two crystallographic sites of Gd2SiO5

Gd2SiO5 is among the interesting and suitable hosts for Er3+ which find extensive applications in the infrared, visible and ultraviolet spectral regions. In order to investigate its potentialities, a prior study of the spectroscopic behaviour of Er3+ substituting for Gd3+ ions in the two crystallographic sites of the host was performed. Absorption, excitation, site-selective emission and time-resolved spectroscopies were employed in the visible spectral region to study transitions between excited 4S3/2 and ground 4I15/2 states. These levels multiplets were attributed to each site separately, and their corresponding 4S3/2 lifetimes (1.8 ± 0.1 μs for site 1 and 3.2 ± 0.1 μs for site 2) were determined.

Tunable and efficient diode-pumped Yb3+: GYSO laser

Effective diode-pumped cw tunable laser action of a new alloyed crystal Yb:Gd(2(1-)x) Y2xSiO5 (Yb:GYSO, x = 0.5) is demonstrated for the first time. The alloyed crystal retains excellent laser properties of Gd2SiO5 (GSO), as well as the favorable growth properties and the desirable physical of Y2SiO5 (YSO). With a 5-at.% Yb: GYSO sample, we achieved 2.44 W output power at 1081.5 nm and a slope efficiency of 57%. And its laser wavelength could be tuned from 1030nm to 1089 nm. (c) 2006 Optical Society of America.

Crystal growth and optical properties of Gd1.99-xYxCe.0.01SiO5 single crystals

Gd1.99-xYxCe0.01SiO5 (Ce:GYSO) crystals (x = 0, 0.0995, 0.199) have been grown by the Czochralski (Cz) method. Crystal structure and the distribution coefficients of Ce have been determined for all three crystals. Spectroscopic measurements indicate that optical transmittance and luminescence intensity of Gd1.99-xYxCe0.01SiO5 (x = 0.0995, 0.199) crystals are Substantially higher than those of Ce:Gd2SiO5 (Ce:GSO), especially at x = 0.0995, which makes them good candidate materials for scintillation applications. The particularly important result is that the alloyed Ce:GYSO crystals can be grown easily by the Cz method and, unlike Ce:GSO, they do not undergo cleavage during the growth process or subsequent mechanical treatment. (c) 2005 Elsevier B.V. All rights reserved.

Growth and spectroscopic characteristics of Yb : GSO single crystal

For the first time, a high optical quality 10 at.% Yb3+-doped gadolinium oxyorthosilicate laser crystal Gd2SiO5 (GSO) was grown by the Czochralski (Cz) method. The segregation coefficient of Yb3+ was studied by the inductively coupled plasma atomic emission spectrometer (ICP-AES) method. The crystal structure has monoclinic symmetry with space group P2(1)/c; this was determined by means of an x-ray diffraction analysis. The absorption spectra, fluorescence spectra and fluorescence decay curves of Yb3+ ions in a GSO crystal at room temperature were also studied. Then, the spectroscopic parameters of Yb:GSO were calculated. The advantages of the Yb:GSO crystal include high crystal quality, quasi-four-level laser operating scheme, high absorption cross-sections and particularly broad emission bandwidth (similar to 72 nm). The results indicated that the Yb:GSO crystal seemed to be a very promising laser gain medium in diode-pumped femtosecond laser and tunable solid state laser applications when LD pumped at 940 and 980 nm.