Rare-Earth Lasers

Abstract

The laser is a source of coherent radiation in the optical region of the spectrum. The common characteristic of all laser types is the population inversion in the active element of the laser. The conditions for laser action were first described by Schawlow and Townes [1] in 1958. The first demonstration of laser action was achieved in ruby by Maiman [2]. In the last 15 years a systematic search was conducted for new laser systems using trivalent and divalent rare earths in a great variety of crystals [3][4][5], glasses [6-20] and liquids [21][22][23].Since these data are available we shall concentrate mostly on the recent development in the rare earth laser art which had a tremendous impact in the first half of the seventies. At the present time of energy crisis it is realized that the most noteworthy property of the laser is its ability to produce an energy concentration in space and time even greater than that found in the heat of nuclear explosion. A huge laser program is now being carried out at the Lawrence Livermore Laboratories, also in Los Alamos Scientific Laboratory, Sandia Laboratories, KMS Fusion Inc. and at Rochester [24] under sponsorship of the United States Energy Research and Development Administration (ERDA).All these projects move to a final goal to initiate the thermonuclear reaction by irradiating a deuterium-tritium pellet with high energy laser of a few picoseconds duration. The vapor evolved from the pellet surface creates a back pressure that compresses and heats the pellet's center. During the thermonuclear burning the pellet is held together by the inertia of its mass.The first direct experimental proof that the neutrons produced in laser-driven implosions are of thermonuclear origin, was demonstrated at the end of 1975 at the Lawrence Livermore Laboratory [25]. The other activities of this laboratory are connected with 1) laser isotope separation to demonstrate the scientific possibility of using a laser induced process to alter the isotopic ratios of chemical elements especially uranium, 2) laser research and development to identify fruitful areas of new laser research and provide the necessary scientific data base for evaluating new lasers. Also recently KMS Fusion Inc. reported a development of "plasma spatial fllter" which eliminates hot spots in high-power glass lasers providing an improvement in the quality of the laser beam.Neodymium doped glass lasers are the best understood high-energy short pulse lasers now available. Because of this understanding we know how to optimize the R. Reisfeld et al., Lasers and Excited States of Rare Earths

Recent progress in trivalent europium (Eu3+)-based inorganic phosphors for solid-state lighting: an overview

“…We can use the formula proposed by Reisfeld and Jorgensen to calculate the positions of CT of the RE ions, as well as the oxygen-to-metal charge transfer (CT) band (M = Mo, W, Nb, Ta). 17,18 E ct (cm −1 ) = [ χ opto ( X ) − ( χ opt ( M )] × 30 000 cm −1 …”

Temperature-Dependence of Multiphonon Relaxation of Rare-Earth Ions in Solid-State Hosts

“…(7) and the temperature dependence approximated by Eqs. (8) and (9), the simplified multiphonon relaxation rate is given by 16 …”

“…ΔE corresponds to the energy difference between the lower 1 G 4 and upper 3 F 4 Stark levels for each host and was calculated from data tabulated by Kaminskii. 35 The multiphonon B and α coefficients are from Reisfeld and Jørgensen 16 with the exception of LaBr 3 being from Wright, et al 17 ‡ Multiphonon relaxation dominates over the radiative de-excitation such that no 1.3 μ m ( 1 G 4 → 3 H 5 ) luminescence is observed in SiO 2 . …”

Silver nanowires as plasmonic compensators of luminescence quenching in single up-converting nanocrystals deposited on graphene

“…Rare-earth doped materials are known for their outstanding optical properties, utilizing Stokes and anti-Stokes (up-conversion) luminescence occurring in the visible and infrared spectral ranges [12][13][14] . Due to unique optical properties they have found number of applications in lasers 15 , displays 16,17 , bio-medical contrasts/markers 18,19 and sensors 20 . Recently, their application palette has been significantly extended due to incorporating interactions with graphene [21][22][23][24][25] .…”