High-power diode-pumped Yb^3+:CaF_2 femtosecond laser

Lucca, Andrea; Debourg, G.; Jacquemet, Mathieu; Druon, Frédéric; Balembois, François; Georges, Patrick; Camy, Patrice; Doualan, Jean‐Louis; Moncorgé, R.

doi:10.1364/ol.29.002767

Cited by 173 publications

(87 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Some of the key issues in using nanoscale materials include the location, distribution of trapping centers, electron-phonon interactions and the potential for energy transfer to a luminescent center in a nanostructure. Many of the preparation methods of nanoparticles can be modified to create nanostructured films and nanocomposites, although some types of nanostructures require completely novel approaches [1][2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Optical absorption and Photoluminescence studies in Gamma-irradiated nanocrystalline CaF2

urangappa¹,

Lakshminarasappa²

2011

J Nanomedic Nanotechnol

View full text Add to dashboard Cite

Calcium fluoride (CaF 2 ) nanoparticles were synthesized by co-precipitation method and characterized by powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM). Also, optical absorption (OA) and photoluminescence (PL) studies on gamma irradiated (γ-rayed) CaF 2 nanoparticles were carried out. The XRD patterns confirmed the cubic crystallinity of the samples and the particle size was found to be ~25 nm. The purity of the synthesized nanoparticles was confirmed by FTIR spectrum. The morphological features studied using SEM revealed the agglomerated and porous nature of nanoparticles. γ-rayed CaF 2 nanoparticles showed a prominent absorption with a peak at ~360 nm besides three weak but well separated absorptions at ~ 267, 442 and 510 nm. The various defect centers responsible for the absorption peaks were identified. The PL studies of samples showed strong emissions at ~396 nm and 425 nm. The observed PL emissions are attributed to defects created in nanocrystalline CaF 2 .Citation: Pandurangappa C, Lakshminarasappa BN (2011) Optical absorption and Photoluminescence studies in Gamma-irradiated nanocrystalline CaF 2 .

show abstract

Section: Introductionmentioning

confidence: 99%

Optical absorption and Photoluminescence studies in Gamma-irradiated nanocrystalline CaF2

urangappa¹,

Lakshminarasappa²

2011

J Nanomedic Nanotechnol

View full text Add to dashboard Cite

show abstract

“…Recently, what is believed to be the first demonstration of a femtosecond laser based on Yb-doped CaF 2 , which has a thermal conductivity near 10 W / mK, was reported. 12 Pulses as short as 150 fs were obtained with this crystal. Very recently, efficient continuous-wave laser operation has been demonstrated with the new laser crystal Yb: YVO 4 , 13,14 which exhibits strong absorption near 985 nm with a bandwidth [full width at half maximum (FWHM)] of ϳ9 nm (that is suitable for pumping by commercially available laser diodes), and a broad and smooth gain spectrum comparable to that of the crystals mentioned above.…”

mentioning

confidence: 97%

Femtosecond pulse generation with a diode-pumped Yb^3+:YVO_4 laser

et al. 2005

View full text Add to dashboard Cite

A diode-pumped Yb: YVO 4 laser has been passively mode locked for the first time, to our knowledge. 120 fs pulses with an average output power of 300 mW and a peak power as high as 14.5 kW are obtained by use of a semiconductor saturable-absorber mirror for passive mode locking. The optical spectrum has a 10 nm bandwidth (full width at half-maximum) and is centered at 1021 nm. having a comparatively high thermal conductivity of 11 W / mK. However, the emission bandwidth of this material limited the pulse duration to 700-800 fs, or to 340 fs in a low-power laser.3 Much shorter pulses (near 100 fs and less) were obtained with a number of crystals with a broader emission band, such as Ybdoped KYW, KGW, GdCOB, BOYS, etc., 4-10 and with Yb:glass.11 However, these materials have a low thermal conductivity of approximately 2 -3 W / mK, which severely limits their potential for high-power operation. Recently, what is believed to be the first demonstration of a femtosecond laser based on Yb-doped CaF 2 , which has a thermal conductivity near 10 W / mK, was reported.12 Pulses as short as 150 fs were obtained with this crystal. Very recently, efficient continuous-wave laser operation has been demonstrated with the new laser crystal Yb: YVO 4 , 13,14 which exhibits strong absorption near 985 nm with a bandwidth [full width at half maximum (FWHM)] of ϳ9 nm (that is suitable for pumping by commercially available laser diodes), and a broad and smooth gain spectrum comparable to that of the crystals mentioned above. The thermal conductivity of yttrium vanadate crystals is 5.23 W / mK along the c axis and 5.10 W / mK along the a axis, 15 i.e., lower than in YAG; however, approximately 40% higher than, e.g., in the well-known KGW, 4 whereas the gain spectrum is smoother than for Yb: CaF 2 . Here we report for the first time to our knowledge on femtosecond pulse generation with a diode-pumped Yb: YVO 4 laser that is passively mode locked with a semiconductor saturable-absorber mirror (SESAM). 16,17 The laser experiments were carried out with a simple delta cavity (Fig. 1). To obtain good alignment stability, the laser cavity was designed to operate in stability zone I. 18 As the gain medium we used a 2 -mm-thick Yb: YVO 4 crystal with 3-at. % ytterbium concentration at Brewster incidence. The crystal orientation was chosen for polarization ͑E ʈ c͒ where the absorption and stimulated-emission cross sections have higher values than for polarization, as shown in our previous work.13 Absorption and stimulated-emission cross-section spectra are presented in Fig. 2. An 8-W continuous-wave (cw) fibercoupled diode laser with a core diameter of 100 m and a numerical aperture of 0.22 operated around 980 nm with a spectral bandwidth of 6 nm was used for longitudinal pumping of the gain medium along the a axis. Longitudinal pumping through spherically curved mirror M1 has problems because of the narrow spectral interval (of ϳ40 nm) between the pump and the laser wavelengths. Because we used a standard / 4 coating optimized for high reflectivi...

show abstract

“…However, these materials have low thermal conductivity of approximately 2 -5 W / ͑mK͒, which limits their potential for high-power operation. With Yb-doped CaF 2 , which has thermal conductivity of 9.7 W / ͑mK͒, average power up to 880 mW with pulses as short as 150 fs was reported [14]; however, a rather low absorption cross section of this crystal makes it not suitable for thin-disk lasers. Sesquioxides, such as Lu 2 [17].…”

mentioning

confidence: 99%

Spectroscopy and femtosecond laser performance of Yb^3+:YAlO_3 crystal

et al. 2008

View full text Add to dashboard Cite

We report what we believe to be the first demonstration of cw and passively mode-locked Yb 3+ : YAlO 3 (Yb:YAP) laser operation under diode pumping. Spectroscopic properties of a 0.6 at.% Yb 3+ -doped YAP single crystal were investigated. Output power up to 1.2 W with slope efficiency of 64.5% in the cw regime and 225 fs pulse duration with average power of 0.8 W from a mode-locked Yb:YAP laser were demonstrated. OCIS codes: 140.3380, 140.3480, 140.3615, 140.4050, 140.5680. Present widespread use of efficient InGaAs laser diodes and favorable electronic structure of ytterbium ions stimulate interest in Yb 3+ -doped solid-state materials for diode-pumped high-power lasers emitting in the spectral range near 1 m. Broad gain bandwidth of these media has stimulated their applications for generation of ultrashort pulses in modelocked regime. © 2008 Optical Society of AmericaSo far, the highest average output power of 60 W with ultrashort pulses has been obtained with a thindisk Yb:YAG laser, passively mode-locked with a semiconductor saturable-absorber mirror (SESAM) [1]. The thermal conductivity of YAG is about 13 W / ͑mK͒. However, the emission bandwidth of Yb:YAG limits the pulse duration to only 700-800 fs in a thin-disk laser, or to 340 fs in a bulk laser [2]. Much shorter pulse durations were reported for a number of crystals with broader emission bands, such as Yb-doped YVO 4 [19,20]. It was shown that Yb 3+ ͑15 at.% ͒ : YAP crystal is a potential candidate for compact, efficient thin-chip lasers; in addition, its broad emission band allows the generation of ultrashort pulses. The latest description and analysis of Yb:YAP crystal growth, structural characterization, and spectroscopic properties were published in [21]. In this study, Boulon et al. reported experimental decay-time dependence on Yb 3+ -dopant concentrations, and room-temperature absorption and emission cross section spectra along the a axis were given. Radiative lifetime of an upper-laser level was estimated there to be 0.6 ms, which has a large discrepancy with the decay time published in [19].In our study polarized absorption spectra of Yb 3+ ͑0.6 at.% ͒ : YAP at room temperature were measured by a Varian CARY-5000 spectrophotometer. The content of ytterbium ions in crystal was measured by means of a Tescan VEGA II LMU scanning electron microscope with Oxford INCA Energy 350 energy dispersive x-ray analyzer and was estimated to be 1.17ϫ 10 20 cm −3 . The cross-section spectra for three polarizations are shown in Fig. 1. Strong absorption is found for E ʈ c light polarization. A peak absorption cross-section at 978.2 nm is about 6.6 ϫ 10 −20 cm 2 , however, with comparatively narrow bandwidth of about 4 nm. For a and b polarizations maximal absorption cross sections near 978.5 nm are 0.97ϫ 10 −20 cm 2 and 1.38ϫ 10 −20 cm 2 , respectively. The stimulated emission cross sections are also given in Fig. 1. They were calculated by use of a modified

show abstract

High-power diode-pumped Yb^3+:CaF_2 femtosecond laser

Cited by 173 publications

References 19 publications

Optical absorption and Photoluminescence studies in Gamma-irradiated nanocrystalline CaF2

Optical absorption and Photoluminescence studies in Gamma-irradiated nanocrystalline CaF2

Femtosecond pulse generation with a diode-pumped Yb^3+:YVO_4 laser

Spectroscopy and femtosecond laser performance of Yb^3+:YAlO_3 crystal

Contact Info

Product

Resources

About