Nataliya Rubtsova, Sergey Kochubei, Alexander Kovalyov, Valery Preobrazhenskii, Mikhael Putyato, Oleg Pchelyakov, Boris Semyagin, Timur Shamirzaev, Nikolay Kuleshov, Viktor Kisel, Sergey Kurilchik
Semiconductor nanostructures (multiple quantum wells type) design and manufacturing are developed for ternary and quaternary A3B5 compounds. Characterization of SA by subpicosecond resolution pump-probe technique
was made for SA samples for Yb3+:KY(WO4)2 and Nd3+:KGd(WO4)2 lasers. Recovery kinetics contains the
"fast" (hundreds fs) and "slow" (hundreds ps) parts. Method of recovery time shortening based on ultra-violet
laser irradiation of SA was investigated; it showed the possibility to reduce the "slow" relaxation time by an
order of magnitude. Another approach based on application of nanostructured barriers between quantum wells
proved also quite suitable for recovery time shortening. A special method of a reflecting interferometer for
complete amplitude and phase characterization of laser mirrors was developed and tested. SA mirrors operating
in Yb3+:KY(WO4)2 and Nd3+:KGd(WO4)2 lasers gave promising results for peak power and pulse duration.
Progress in the development of efficient and reliable diode-pumped femtosecond laser systems based on both Kerr-lens
and saturable-absorber mode locking is reported. Efficient Kerr-lens mode locking in diode pumped ytterbium-doped
lasers, namely Yb:KY(WO4)2 (Yb:KYW) and Yb:YVO4, is demonstrated with average output powers in excess of 1W, pulse durations around 100fs and electrical-to-optical efficiencies that exceed 15%. Novel semiconductor saturable
absorbers based on InAs/InGaAs quantum dots are described and their applicability for efficient femtosecond pulse
generation from near-infrared solid-state lasers is discussed. Efficient passive mode locking in the spectral regions
around 1.3&mgr;m and 1.55&mgr;m in Cr:forsterite and the more recently developed Er, Yb:YAl3(BO4)3 crystalline lasers has been demonstrated using low-loss InGaNAs saturable absorbers. A few examples of applications for this category of robust and efficient femtosecond lasers have been included. Specifically, the characteristics of a femtosecond visible
light source producing pulses as short as 200fs at 520nm are outlined.
Glass doped with PbS quantum dots is presented as a saturable absorber for passive Q-switching of diode-pumped
Tm:KYW laser. Output pulses with energy of 43 μJ at the repetition rate of 2.5 kHz were obtained. The slope efficiency
with respect to the absorbed pump power was ~20%. Being compared in the same laser, PbS-doped glass saturable
absorber outperforms Cr:ZnSe one in output power, pulse energy and slope efficiency.
Continuous wave and Q-switched diode-pumped laser operation of Yb3+ :NaLa(MoO4)2 single crystal was demonstrated for the first time to our knowledge. A cw output power of 220 mW and slope efficiency of 46% were obtained. Q-switched laser operation was achieved with pulse duration of 60 ns. An average output power and slope efficiency were
70 mW and 22% respectively.
The development of femtosecond (fs) lasers has continued rapidly since the demonstration of fs Ti:Sapphire systems in 1989. Recent research has yielded lasers which offer greatly enhanced performance in all areas. In this document we describe the development of femtosecond lasers with electrical to optical efficiency > 14%, pulse repetition frequencies > 4GHz and compact and stable cavities. We further outline the use of such lasers for the generation of high power visible femtosecond pulses and their application within systems environments for ultrahigh speed data communications, ultrafast optical switching and optical analogue to digital conversion. We also describe progress in the development of femtosecond lasers based on both active and passive semiconductor quantum dot components.
Mechanisms of refractive index changes in intensively pumped Yb-doped crystals (Yb:YAG, Yb:KYW, Yb:KGW, and Yb:YVO4) were studied using both a polarization interferometer and the transient grating method at the testing wavelength of 633 nm. The electronic component strongly predominated over thermal index changes in the experimental conditions. The polarizability difference of the excited and unexcited Yb3+ ions (of the ground state and the excited metastable level 2F7/2) was determined.
Here we report, for the first time to our knowledge, a cladding-pumped passively Q-switched Er-Yb codoped fiber laser with Cr2+:ZnSe and Co2+:MgAl2O4 as saturable absorbers. The maximum average output power for both crystals was 1.4 W, with typical pulse energy was 20 μJ corresponding to 60 W peak power. The pulse duration could be varied between 370 - 700 ns and repetition rate between 20 and 85 kHz by adjusting the pump power.
Polarized differential absorption spectra of Cr4+- doped forsterite have been studied using a picosecond pump- probe technique. For pump beam and probe beam polarization parallel to the axis, an excited state absorption in the 450-800 nm region is observed and assigned to the 3T2yields3T1(3P) transition of Cr4+ ion. The lifetime of the 3T1(3F) state is estimated to be less than 15 ps.
We describe a computational method for calculating the electric field, generated by a periodical set of electrodes, that are placed on the surface(s) of a 9/65/35 PLZT electro-optic ceramics layer. This method is based on the introduction of two auxiliary functions that describe the density of electric charge distribution on the electrodes with different potentials. The problem is then reduced to the solution of the two integral equations in these functions. The coordinate transforms of each of the two equations, which map electrode areas onto the whole period, modify these integral equations into two coupled infinite sets of algebraic equations for coefficients of expansion into a Fourier series of auxiliary functions. For the new sets of expansion coefficients, the sets of equations become decoupled ones. These equations were solved numerically by cutting to a finite number of equations. With the help of this method, the three schemes of electrode connections were analyzed. The dependences of the half-wave voltage and the switching energy on the electrode spatial frequency and on the relative electrode width were determined. These dependences give the possibility to obtain the optimal electrode pattern of the schemes and find out the optimal scheme of electrode connections.
Optical absorption, luminescence, saturation of absorption and lifetime measurements have been carried out on Co-doped MgAl2O4 and ZnGa2O4. The crystal field parameters are estimated for the tetrahedral Co2+ ion. Three luminescence bands observed in the visible and near infrared are assigned to transitions from the 4T1(4P) level to the lower levels 4A2(4F), 4T2(4F), and 4T1(4F), respectively. Strong luminescence quenching due to nonradiative decay processes is observed MgAl2O4:Co. Saturation of Co2+ absorption at 540 nm is measured and the absorption cross section is estimated to be 2.1 + 0.2 X 10-19 cm2 in MgAl2O4.
The results of theoretical analysis of viscoelastic SLM with electrically controlled deformable surface characteristics are presented. The new effective technique was elaborated for electric field and surface relief calculation in SLM. The characteristics, which are useful for SLM's application in holographic systems, have been obtained with this technique.
The results of the theoretical analysis of electric field structure in a spatial light modulator with viscoelastic deformable layers controlled by addressing a CMOS active matrix are presented.
Results of theoretical and experimental investigations, devoted to the analysis and optimization of optoelectronic image formation devices (IFD) on the basis of deformable polymer films (DPF) at the expense of choice of the polymer material rheology, electric field distribution in DPF by means of electrode raster and heat deformation regime is presented. For DPF structure investigations the tunnel electron microscopy technique has been used.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.