Doped Yttrium Aluminum Garnet Crystal Research Articles

Coherent control of the photonic spin Hall effect by Er3+ ion concentration in an Er3+-doped YAG crystal

We theoretically investigate the effect of doped Er3+ ion concentration on the spin Hall effect (SHE) of light reflected from a Kretschmann-Raether (K-R) structure. In such a structure, an Er3+-doped yttrium aluminum garnet (YAG) crystal acts as the substrate. The excitation of surface plasmon resonance(SPR) leads to the enhancement of the spin splitting of the reflected beam in the resonance reflection dip. Due to the variation of electric dipole moment and energy level lifetime induced by Er3+ ion concentration, the spin-dependent transverse shift is sensitively dependent upon Er3+ ion concentration. Furthermore, under different concentrations of Er3+ ion, the intensity and detuning of the control field have different effects on the magnitude, sign and position of the transverse shift. More importantly, the photonic SHE can be significantly enhanced via choosing the suitable values of the control intensity and detuning at 15% Er3+ ion concentration. Therefore, our scheme may provide a basis for selecting suitable Er3+ ion concentration to enhance the SHE of light in future integrated systems.

Control of an electromagnetically induced grating by Er3+ ion concentration in an Er3+-doped YAG crystal

We investigate the effect of doped E r 3 + ion concentration on an electromagnetically induced grating in an E r 3 + -doped yttrium aluminum garnet (YAG) crystal. Due to the change of electric dipole moment and spontaneous emission decay induced by E r 3 + ion concentration, the Fraunhofer diffraction of the solid-state grating is sensitively dependent upon E r 3 + ion concentration. The three-level E r 3 + ion system with a closed loop leads to probe gain appearing in some concentrations of the E r 3 + ion, which significantly improves the first-order diffraction efficiency of the solid-state grating. Furthermore, it is demonstrated that the relative phase, signal detuning, and grating thickness have different effects on the first-order diffraction efficiency of the solid-state grating under different concentrations of the E r 3 + ion. Therefore, our scheme may provide a basis for selecting a suitable concentration to realize high-efficiency optical switching and routing in future integrated systems.

One- and two-dimensional electromagnetically induced gratings in an Er3+ - doped yttrium aluminum garnet crystal

A coherently prepared Er3+-doped yttrium aluminum garnet (YAG) crystal with a four-level ionic configuration is exploited for realizing one-dimensional (1D) and two-dimensional (2D) electromagnetically induced gratings (EIGs). Owing to the probe gain induced by the incoherent pump, the diffraction efficiency of the crystal grating, especially the first-order diffraction, can be significantly improved via increasing the incoherent pumping rate or decreasing the probe detuning. The enhancement of the grating diffraction efficiency originates from the interference between the gain and phase gratings. It is also demonstrated that the diffraction of the crystal grating can be dynamically controlled via tuning the intensity and detuning of the standing-wave driving field or the concentration of Er3+ ion. More importantly, the probe energy of the diffraction side lobes around the central principle maximum is comparable to that of the first-order diffraction field for small driving intensity or large driving detuning. Our scheme may provide a possibility for the active all-optical control of optical switching, routing and storage in fiber communication wavelengths.

Enormous enhancements of the Kerr nonlinearity at C-band telecommunication wavelength in an Er3+-doped YAG crystal

A novel solid configuration is proposed to achieve a giant Kerr nonlinearity with reduced absorption under conditions of slow light levels. It is shown that an enhanced Kerr nonlinearity accompanied with negligible absorption can be obtained just through the proper tuning of intensity of coherent driving field at C-band telecommunication wavelength which is practical for communication applications. Moreover, the impact of incoherent pump field as well as frequency detuning of coherent field on manipulating the linear and nonlinear optical properties of the yttrium–aluminum-garnet (YAG) crystal medium is discussed. The presented results may be of interest to researchers in the field of all-optical signal processing and solid-state quantum information science.

The Applications of Terahertz Spectroscopy in Functional Optical Materials Researches

Terahertz radiation refers to the electromagnetic wave whose frequency is usually defined between 0.1 and 10 THz (1 THz=1012Hz). With the development of the emission and detection technologies of THz radiation, terahertz time-domain spectroscopy (THz-TDS) has been widely used in medical diagnosis, security inspection and materials characterization. In this paper, we introduced briefly the progress of terahertz measurement technologies, and then reviewed the applications of THz spectra in functional materials researches. As two important functional optical materials, TiO2nanoparticles and yttrium aluminum garnet (YAG) crystal have been investigated with THz-TDS. We introduced the electron injection process in TiO2studied by time resolved THz spectroscopy which is reported in the literature, and then presented our own work, the THz optical constants of undoped and Tm3+doped YAG crystals.

X-ray luminescence based spectrometer for investigation of scintillation properties

A new x-ray luminescence based spectrometer was developed and installed to examine the scintillation properties of materials while revealing the origins of luminescence and investigating trapping defects. Measurements were performed on a number of undoped and Ce doped yttrium aluminum garnet crystals and various luminescence centers were characterized. The measured x-ray luminescence spectra provide information about the spectral range and the scintillation efficiency and linearity. The efficiency of charge-carriers production due to x ray, their energy transfer to the luminescence centers, and the efficiency of luminescence are all reflected in the efficiency of x-ray luminescence.

Temperature and concentration dependence of spectroscopic properties of Nd3+-doped yttrium aluminum garnet crystal

Abstract The optical absorption spectra of yttrium aluminum garnet (YAG) crystals doped with Nd3+ ions with different concentrations (0.6 at%, 1.0 at%, 1.2 at%) at the temperature range from 300 K to 500 K have been measured. The calculated Judd–Ofelt (JO) parameters Ωt (t=2, 4, 6) based on the spectra have been used to predict the radiative transition probabilities, branching ratios and radiative lifetimes of the transitions from 4F3/2 level to the lower levels (4I13/2, 4I11/2, 4I9/2) at each concentration and temperature. The three JO parameters Ωt (t=2, 4, 6), according to the calculation, decrease with the increasing doped concentration at each temperature. The JO parameters Ω2 and Ω4 increase, while the parameter Ω6 decreases with the increasing temperature at each concentration. The branching ratios and radiative transition probabilities of the transitions from the 4F3/2 level to 4I13/2 and 4I11/2 levels decrease, while the transition from the 4F3/2 level to 4I9/2 level increases with the increasing temperature. The obtained results at each concentration and temperature are discussed.

Strong visible and near infrared luminescence in undoped YAG single crystals

Strong luminescence peaks were observed at 700 and 800 nm in undoped yttrium aluminum garnet (YAG) single crystals. They were attributed to low level of iron impurities as confirmed by Glow Discharge Mass Spectrometry analysis. The 800 nm was only excited by high energy band at 270 nm; the reason behind that was discussed. Photoluminescence measurements revealed a large number of luminescence peaks in all YAG crystals regardless of the growth conditions due to native defects and low-level impurities. These luminescence centers have significant effects on the optical properties of rare-earth doped YAG crystals and their performance in laser and scintillation applications. Excitons released in the lattice may be easily captured by iron ions instead of Ce3+ ions and the scintillation output is substantially decreased. Nevertheless, Undoped YAG crystals may have the potential to be developed into efficient scintillators.

Light storage protocols in Tm:YAG

We present two quantum memory protocols for solids: a stopped light approach based on spectral hole burning and a storage in an atomic frequency comb. These procedures are well adapted to the rare-earth ion doped crystals. We carefully clarify the critical steps of both. In one case, we show that the slowing-down due to hole-burning is sufficient to produce a complete mapping of field into the atomic system. On the other side, we explain the storage and retrieval mechanism of the Atomic Frequency Comb protocol. These two critical stages of the protocols are implemented experimentally in Tm 3 + -doped yttrium–aluminum–garnet crystal.

Continuous wave and passively Q-switched laser performance of a Nd-doped mixed crystal Nd:Lu0.5Gd0.5VO4

The authors reported continuous wave (cw) and passively Q-switched laser performances of Nd:Lu0.5Gd0.5VO4 crystal at 1.06μm. cw output power of 6.65W was obtained under the incident pump power of 13.75W with slop efficiency of 51%. In the passively Q-switched operation, the shortest pulse width, largest pulse energy, and highest peak power were achieved to be 6.2ns, 192.5μJ, and 31.06kW, respectively, with Cr4+ doped yttrium aluminum garnet crystals as the saturable absorbers.

Structural and radiation color centers and the dielectric properties of doped yttrium aluminum garnet crystals

The results of experimental and theoretical studies of the spectral and dielectric properties of garnet Y3Al5O12 crystals are analyzed. The crystals studied were grown under different conditions and were either pure or contained iron-group ion impurities (Ti, Cr, Fe). The crystals were studied before and after irradiation by γ rays and high-energy electrons. A model is proposed for the formation of color centers and their influence on luminescent and other optical and dielectric properties.

The phase dependent properties of gain and absorption in an Er3+-doped yttrium aluminum garnet crystal

We theoretically study the phase dependent gain–absorption properties in an Er3+-doped yttrium aluminum garnet crystal. We show that the phenomenon of flattened gain (absorption) can be achieved in a closed three-level system when the total interaction phase equals to π/2 (3π/2). We also can realize a flexible control of the gain equalization with different amplitudes and frequency regions by varying intensities of strong coupling fields. In particular, we point out that the Raman gain always plays an important role in achieving and controlling the flattened gain.

Nd 3 + -doped yttrium aluminum garnet crystal as a near-infrared pressure sensor for diamond anvil cells

Pressure-induced shift of various luminescence lines of Nd3+-doped yttrium aluminum garnet crystal in the pressure range of 0–120kbars and temperatures between 10 and 300K is reported. Spectral positions of all these lines in the region of 900–960nm shift linearly towards lower energies with the pressure coefficient values from −0.01to−0.99cm−1∕kbar in the examined pressure range. Two of these lines have similar pressure coefficients than those of the R lines of Cr3+ in ruby. Therefore, they can be readily used for pressure calibration in diamond anvil cells.

Positive and negative dispersion in an Er^3+-doped yttrium aluminum garnet crystal

We investigate a four-level system in the Er3+-doped yttrium aluminum garnet crystal that can produce an absorption or gain doublet in the probe absorption spectrum when driven by a coherent field and incoherent pumping. It is found that the transparent linear positive or negative dispersion can occur between the doublet lines. We show that the group index of a probe pulse can be manipulated when we control the incoherent pumping and the coherent field.

Quantum Interference Effects on Optical Amplification and the Index of Refraction in a Four-Level System

We construct a four-level system where a metastable state is included in an <TEX>$Er^{3＋}$</TEX> Doped Yttrium aluminum garnet (YAG) crystal. Because of the action of the coherent field, the traditional light amplification with inversion can be exhibited with remarkable variation. As a result, we propose a method to achieve the gain equalization by atomic coherence. At the same time, we find that the high index of refraction accompanied by vanishing absorption can also be reached in this model. We also find that a higher index of refraction with zero absorption can be easily obtained when the coherent field is off resonance.

Quantum-interference effects on the index of refraction in anEr3+-doped yttrium aluminum garnet crystal

A four-level system is proposed to produce large index of refraction accompanied by vanishing absorption in the Er{sup 3+}-doped yttrium aluminum garnet crystal. It is found that the separation of the two absorption peaks and the maximum value of index of refraction with zero absorption can be adjusted by changing the coherent field and the incoherent pumping. It is shown that a higher index of refraction with zero absorption can be easily obtained when the coherent field is off resonance.

Regularities of the neodymium distribution in doped yttrium aluminum garnet crystals grown from solution in the melt

Get PDF Email Share Share with Facebook Tweet This Post on reddit Share with LinkedIn Add to CiteULike Add to Mendeley Add to BibSonomy Get Citation Copy Citation Text V. G. Ivanov , "Regularities of the neodymium distribution in doped yttrium aluminum garnet crystals grown from solution in the melt," J. Opt. Technol. 68, 306- (2001) Export Citation BibTex Endnote (RIS) HTML Plain Text Citation alert Save article

Enhanced absorption by stimulated emission in three excited states of Er3+ in yttrium aluminum garnet

Using a laser diode modulated at 250 and 500 MHz, dependence of enhanced absorption on both sample length and temperature was investigated in an erbium doped yttrium aluminum garnet crystal. The transmitted laser intensity decreased with a decay time of 300 ps for sample lengths greater than 3.0 mm and temperatures higher than 50 K when the incident laser intensity increased. In addition, an emission peak was observed near 835 nm corresponding to the transition from the S3/24 level to the I13/24 in Er3+. It was suggested that the enhanced absorption was caused by stimulated emission in three excited states.

Numerical Analysis and Dependence of Negative Nonlinear Absorption Effect on Modulation Degree of Incident Laser.

The dependence of the negative nonlinear absorption effect on modulation degree of an incident laser was investigated in an erbium doped yttrium aluminum garnet crystal which has a five-level system: absorption can occur between a ground level and an excited level (4I15/2-4I9/2) and between two other excited levels (4I13/2-2H11/2) in Er3+. According as modulation degrees of the incident laser decreased, the transmitted laser waveform was inverted against the incident one for incident modulation degree under 90% and sample lengths greater than 2mm. By calculating rate equations based on an analytical model for the five-level system, it was confirmed that the enhanced absorption was caused by stimulated emission from 4S3/2 level to 4I13/2 level and close agreement between observed and calculated values was obtained in the relation between transmitted modulation degree and incident one.

Enhanced Absorption Phenomena in Negative Nonlinear Absorption Effects.

A negative input-output characteristic was obtained in an erbium doped yttrium aluminum garnet crystal which has multiple-level energy structure: absorption can occur between a ground level and an excited level (4I15/2-4I9/2) and between two other excited levels (4I13/2-2H11/2) in Er3+. According as modulation degrees of the incident laser decreased, the transmitted laser waveform was distorted and eventually inverted against the incident one in case that the modulation degree was less than 0.5. It is suggested that an enhanced absorption phenomenon takes place since the excited state absorption from 4I13/2 to 2H11/2 and that a 4S3/2 level plays an important role. Because the time-dependence of this phenomenon matches a life time of the 4S3/2 level. By considering multiple excited state absorption in detail, active functions such as an optical signal inverter could be derived from the negative nonlinear absorption effect.