J. A. Sanz García

Nd3+ ion based self frequency doubling solid state lasers

Abstract Spectral and laser properties of three non-linear crystals (LiNbO3, LaBGeO5 and YAl3(BO3)4) activated with Nd3+ ions have been investigated. The main laser parameters (absorption and emission cross section, radiative lifetime and quantum efficiency) are determined and compared by means of optical spectroscopy. Optical spectroscopy is also used to estimate losses due to second harmonic (SH) self-absorption, energy transfer, excited state absorption and non-equivalent Nd centres. Continuous wave laser properties of the crystals in the fundamental and SH wavelengths are investigated under similar cavity geometry and pumping conditions using a tunable Ti–sapphire pump laser.

Continuous-wave laser oscillation at 929nm from a Nd3+-doped LiNbO3:ZnO nonlinear laser crystal: A powerful tool for blue laser light generation

This work reports on room-temperature continuous-wave laser action at 929nm from a Nd3+:LiNbO3 nonlinear laser crystal co-doped with ZnO. The spectroscopic parameters of the quasi-three-level F3∕24→I9∕24 laser channel are discussed. In nonoptimal preliminary experiments, pump power at threshold was found to be as low as 105mW.

Optical absorption intensities and fluorescence dynamics of ions in

Optical absorption and fluorescence spectra have been systematically investigated in -doped crystals. The energy position and symmetry character of the Stark levels in the near-infrared region are deduced. The room-temperature absorption line strengths have been experimentally determined and the theory of Judd and Ofelt is used to obtain the radiative lifetimes and branching ratios of the emitting and states. Non-radiative relaxation processes are found to contribute to the transition probabilities of both states. In the case of the multiplets, a multiphonon relaxation process with an effective phonon energy of accounts for the temperature dependence of the lifetime. The -state luminescence shows a non-exponential decay time which indicates the existence of an energy transfer process. This energy transfer process exhibits a Boltzmann-type temperature dependence and is attributed to two-phonon-assisted energy transfer.

Continuous wave laser radiation and self-frequency-doubling in ZnO doped LiNbO3:Nd3+

Abstract We report on continuous wave stable laser action and self-frequency-doubling at room temperature in the system LiNbO3:Nd3+, codoped with ZnO to avoid photorefractive damage effects. The main parameters related to infrared laser action in this system are discussed and the optical quality of the crystals is investigated by measuring the optical losses due to scattering in laser experiments.

Fluorescence bands of Nd3+ sites in LiNbO3:Nd,Mg laser system

This paper presents a systematic investigation on the fluorescence (emission and excitation) spectra for the different Nd3+ sites which appear in the LiNbO3:Nd,Mg laser crystal. The study includes the spectral region associated to the 4F3/2 → 4I11/2 and 4F3/2 →4I9/2 radiative transitions. Three sites, denoted as Nd‐1, Nd‐2 (which also appear in the crystal without Mg2+), and Nd‐Mg, have been optically characterized and their corresponding energy levels reported. This information should be taken into account when making a laser with this material.

Optical spectroscopy of Er3+-doped Bi12SiO20 piezoelectric crystal

Abstract Photoluminescence of Er 3+ ions in a Bi 12 SiO 20 crystal is investigated under excitation in the near infrared region ( 4 I 15/2 → 4 I 9/2 transition) at low temperature. Two non-equivalent Er 3+ centers are detected in the crystal. Besides the one photon infrared emission ( 4 I 11/2 → 4 I 15/2 ), up-converted luminescence in the green ( 4 S 3/2 → 4 I 15/2 ) and red ( 4 F 9/2 → 4 I 15/2 ) spectral regions and down-converted emission ( 4 S 3/2 → 4 I 13/2 ) in the near infrared region have been observed and resolved for each type of Er center. The mechanisms responsible for the conversion process are analyzed. The position of the Stark energy levels are obtained for each center for different Er 3+ multiplets.

Rare earth ion doped non linear laser crystals

We show how non linear crystals activated with Yb3☎ or Nd3☎ ions can be used to develop diode pumped solid state lasers emitting in the visible region of the electromagnetic spectrum. For this purpose we have selected relevant examples of systems investigated in our laboratory.

Photorefractive Damage Resistant Zn-Diffused Optical Waveguides in LiNbO 3 : Nd 3+ and Laser Operation

This work reports the fabrication of photorefractive damageresistant channel waveguides by a two-step Zn-diffusion technique in LiNbO 3 :Nd 3+ crystals and the demonstration of laser operation at room temperature at u =1.085 w m.

Codoping Effects on the Laser Gain of Neodymium Activated Lithium Niobate Crystals

Congruent LiNbO 3 crystals activated with Nd 3+ (codoped with MgO, ZnO or Sc 2 O 3 ) have been characterised by spectroscopic and laser experiments. By optical absorption spectroscopy the distribution of Nd 3+ ions has been studied. The highest Nd incorporation was observed for Mg (5%), Nd(4%) melt concentrations, where saturation takes place. The optical quality of these crystals has been tested measuring the corresponding internal loss factor by laser experiments.

Phase transition induced gain depression in Nd3+:SBN lasers

In this work the origin of the phase transition induced gain depression in diode pumped Nd3+ doped Sr0.6Ba0.4(NbO3)2 lasers has been systematically investigated. The mechanisms capable of intracavity beam distortions are discussed and their relative contribution to the gain depression is investigated. We also provide evidence of two effects: a phase transition induced polarization switching and an enhancement in the laser performance when phase transition is overcome.