The refractive indices of new Nd3+ : GdVO4, Tm3+ : GdVO4, and Er3+ : GdVO4 laser crystals were determined with an error of ±5×10-5 in the range 400–1100 nm. The birefringence of these crystals was on the average 0.24, and the dispersion was described by the formula 1/Δn2 = a+ b/λ2. The thermal conductivity of the Nd : GdVO4 crystal (atomic neodymium concentration 1.3%) was determined in the temperature range 77-300 K. At 300 K the conductivity along the direction was 11.7 W m-1 K-1, which was higher than the conductivity of Nd : YAG crystals.

https://iopscience.iop.org/article/10.1070/QE1995v025n12ABEH000556/pdf

GdVO4 as a new medium for solid-state lasers: some optical and thermal properties of crystals doped with Cd3+, Tm3+, and Er3+ ions

Ho3+-doped and Ho3+/Yb3+-codoped lead bismuth gallate (PBG) oxide glasses were prepared and their spectroscopic properties were investigated. The derived Judd–Ofelt intensity parameters (Ω2=6.81×10−20 cm2, Ω4=2.31×10−20 cm2, and Ω6=0.67×10−20 cm2) indicate a higher asymmetry and stronger covalent environment for Ho3+ sites in PBG glass compared with those in tellurite, fluoride (ZBLAN), and some other lead-contained glasses. Intense frequency upconversion emissions peaking at 547, 662, and 756 nm as well as infrared emissions at 1.20 and 2.05 μm in Ho3+/Yb3+-codoped PBG glass were observed, confirming that energy transfer between Yb3+ and Ho3+ takes place, and a two-phonon-assisted energy transfer from Yb3+ to Ho3+ ions was determined by the calculation using phonon sideband theory. The 1.20 μm emission observed was primarily due to the weak multiphonon deexcitation originated from the small phonon energy of PBG glass (∼535 cm−1). A large product of emission cross-section and measured lifetime (9.93×10−25...

Judd–Ofelt analysis, frequency upconversion, and infrared photoluminescence of Ho3+-doped and Ho3+/Yb3+-codoped lead bismuth gallate oxide glasses

High power diode-pumped continuous wave (CW) and Q-switch operation of Tm,Ho:YVO4 laser is reported. Using two Tm,Ho:YVO4 rods in a single cavity, up to 20.2 W of CW output lasing at 2054.7 nm was obtained under cryogenic temperature of 77 K with an optical to optical conversion efficiency of 32.9%. For Q-switch operation, up to 19.4 W of output was obtained under 15 kHz pulse repetition frequency (PRF) with a minimum pulse width of 24.2 ns. In addition, different pulse repetition frequencies of Q-switch operation with 10.0 kHz, 12.5 kHz and 15.0 kHz were investigated comparatively.

http://iopscience.iop.org/article/10.1002/lapl.201010074/pdf

High power diode‐pumped continuous wave and Q‐switch operation of Tm,Ho:YVO4 laser

Synthesis and infrared spectroscopic properties of Tm3+-doped phosphate glasses

Tm:KGd(WO/sub 4/)/sub 2/ is studied as a three-level laser on the /sup 3/F/sub 4/ /spl rarr/ /sup 3/H/sub 6/ transition and a tunable source in the 2-/spl mu/m spectral range, operating at room temperature. An overall tunability extending from 1790 to 2042 nm is achieved with maximum output powers of 400 mW for an absorbed pump power of 1 W. Various doping levels, pump wavelengths and polarization configurations are compared and the advantages of the monoclinic double tungstates over other Tm-hosts are outlined.

/pdf/efficient-tunable-laser-operation-of-tm-kgd-wo-sub-4-sub-2-gik58vj25c.pdf

Efficient tunable laser operation of Tm:KGd(WO/sub 4/)/sub 2/ in the continuous-wave regime at room temperature

Spectroscopic characterization of the 5 at. % Tm3+:YVO4 crystal has been performed. The peak absorption cross section of the pumping band at 797.5 nm and the peak emission cross section of the laser transition at 1800 nm were determined to be 2.5×10−20 and 1.6×10−20 cm2, respectively. More than 150 nm tunability range is expected for this material. In addition, a possible extension of the tunability range under high‐power pulsed excitation is discussed.

Spectroscopic characterization of Tm3+:YVO4 crystal as an efficient diode pumped laser source near 2000 nm

Spectroscopic measurements were carried out to identify the fundamental optical properties of the Tm3+:YVO4 crystal (5 at.% Tm3+ ion concentration) as a laser medium. Absorption spectra, emission cross section versus wavelength of the 3F4-3H6 laser transition, and effective radiative lifetimes closely related to the laser diode pumping kinetics were derived from the measurements. We developed a rate equation model to describe the laser oscillation characteristics in terms of the lasing spectra. The theoretical results agreed well with the experimental results.

Characterization of a Longitudinally Pumped CW, Room-Temperature Operation of Tm3+:YVO4 Laser

A computer-controlled beam monitoring system for KrF excimer lasers was developed for simultaneous measurement of near and far field patterns and pointing stability of the laser beam at a 250 Hz repetition rate. The system and results obtained are described.

Beam monitoring system for simultaneous measurement of near and far field patterns in high repetition rate KrF lasers.

A narrow band KrF excimer laser device which consists of an oscillator and a double‐pass amplifier with a stimulated Brillouin scattering phase conjugation (SBS‐PC) mirror (double‐pass self‐compensation scheme) was operated with the constant reflectivity of phase conjugation at 100 Hz repetition rate, by vibrating the SBS cell. The dependence of the beam quality on the operating frequency was evaluated for every shot by using a beam profiler. The beam divergence was less than 100 μrad and the fluctuation at the far‐field peak position was less than 10 μrad at 100 Hz with the spectral bandwidth less than 0.2 cm−1.

Beam quality measurement of a narrow band KrF excimer laser with stimulated Brillouin scattering phase conjugate double‐pass amplifier at 100 Hz operation

An imaging system with a two dimensional photo diode array was developed for the excimer laser beam diagnostics. It is featured with a fast frame rate, high spacial resolution, and responsibity at the uv wave length. With a simple optical set up for the imager, we measured a near and a far field pattern simultaneously and the spectral band width of the consecutive KrF excimer laser pulses at 250Hz. These measurements shows our imaging system possesses enough spacial resolution for the beam pattern and spectral measurements.

Kei Ohta

Papers

Spectroscopic characterization of Tm3+:YVO4 crystal as an efficient diode pumped laser source near 2000 nm

Characterization of a Longitudinally Pumped CW, Room-Temperature Operation of Tm3+:YVO4 Laser

Beam monitoring system for simultaneous measurement of near and far field patterns in high repetition rate KrF lasers.

Beam quality measurement of a narrow band KrF excimer laser with stimulated Brillouin scattering phase conjugate double‐pass amplifier at 100 Hz operation

A Diagnostic System For An Excimer Laser Beam