The principal ideas of the thin-disk laser design will be illustrated and the advantages for operating different laser materials will be explained. The results for continuous-wave (CW) and Q-switched ...operation as well as for amplification of short (nanosecond) and ultrashort (picosecond, femtosecond) pulses demonstrate the potential of the thin-disk laser design. The scaling laws for this laser design show that the power limit for CW operation is far beyond 40 kW for one single disk and the energy limit is higher than 3 J from one disk in pulsed operation. Also, the applicability of the thin-disk laser concept to optically pumped semiconductor structures will be discussed. When pumping directly into the quantum wells, the energy defect between the pump photon and the laser photon can be smaller than 5%, thus reducing the waste heat generated inside the semiconductor structure. First results demonstrate the potential of this new concept. Finally, a short overview of the industrial realization of the thin-disk laser technology will be given.
Laser spectroscopy of muonic deuterium Pohl, Randolf; Nez, François; Fernandes, Luis M. P. ...
Science (American Association for the Advancement of Science),
08/2016, Letnik:
353, Številka:
6300
Journal Article
Recenzirano
Odprti dostop
The deuteron is the simplest compound nucleus, composed of one proton and one neutron. Deuteron properties such as the root-mean-square charge radius rd and the polarizability serve as important ...benchmarks for understanding the nuclear forces and structure. Muonic deuterium μd is the exotic atom formed by a deuteron and a negative muon μ⁻. We measured three 2S-2P transitions in μd and obtain rd = 2.12562(78) fm, which is 2.7 times more accurate but 7.5σ smaller than the CODATA-2010 value rd = 2.1424(21) fm. The μd value is also 3.5σ smaller than the rd value from electronic deuterium spectroscopy. The smaller rd, when combined with the electronic isotope shift, yields a "small" proton radius rp, similar to the one from muonic hydrogen, amplifying the proton radius puzzle.
Accurate knowledge of the charge and Zemach radii of the proton is essential, not only for understanding its structure but also as input for tests of bound-state quantum electrodynamics and its ...predictions for the energy levels of hydrogen. These radii may be extracted from the laser spectroscopy of muonic hydrogen (μp, that is, a proton orbited by a muon). We measured the $2{\mathrm{S}}_{1/2}^{\mathrm{F}=0}-2{\mathrm{P}}_{3/2}^{\mathrm{F}=1}$ transition frequency in μp to be 54611.16(1.05) gigahertz (numbers in parentheses indicate one standard deviation of uncertainty) and reevaluated the $2{\mathrm{S}}_{1/2}^{\mathrm{F}=1}-2{\mathrm{P}}_{3/2}^{\mathrm{F}=1}$ transition frequency, yielding 49881.35(65) gigahertz. From the measurements, we determined the Zemach radius, r Z = 1.082(37) femtometers, and the magnetic radius, r M = 0.87(6) femtometer, of the proton. We also extracted the charge radius, r E = 0.84087(39) femtometer, with an order of magnitude more precision than the 2010-CODATA value and at 7σ variance with respect to it, thus reinforcing the proton radius puzzle.
The size of the proton dos Santos, Joaquim M. F; Fernandes, Luis M. P; Liu, Yi-Wei ...
Nature (London),
07/2010, Letnik:
466, Številka:
7303
Journal Article
Recenzirano
The proton is the primary building block of the visible Universe, but many of its properties—such as its charge radius and its anomalous magnetic moment—are not well understood. The root-mean-square ...charge radius, rp, has been determined with an accuracy of 2 per cent (at best) by electron–proton scattering experiments. The present most accurate value of rp (with an uncertainty of 1 per cent) is given by the CODATA compilation of physical constants. This value is based mainly on precision spectroscopy of atomic hydrogen and calculations of bound-state quantum electrodynamics (QED; refs 8, 9). The accuracy of rp as deduced from electron–proton scattering limits the testing of bound-state QED in atomic hydrogen as well as the determination of the Rydberg constant (currently the most accurately measured fundamental physical constant). An attractive means to improve the accuracy in the measurement of rp is provided by muonic hydrogen (a proton orbited by a negative muon); its much smaller Bohr radius compared to ordinary atomic hydrogen causes enhancement of effects related to the finite size of the proton. In particular, the Lamb shift (the energy difference between the 2S1/2 and 2P1/2 states) is affected by as much as 2 per cent. Here we use pulsed laser spectroscopy to measure a muonic Lamb shift of 49,881.88(76) GHz. On the basis of present calculations of fine and hyperfine splittings and QED terms, we find rp = 0.84184(67) fm, which differs by 5.0 standard deviations from the CODATA value of 0.8768(69) fm. Our result implies that either the Rydberg constant has to be shifted by −110 kHz/c (4.9 standard deviations), or the calculations of the QED effects in atomic hydrogen or muonic hydrogen atoms are insufficient.
The design ideas of thin disk lasers will be explained in detail. Experimental results for continuous wave operation and for pulsed operation show the capability for building high power lasers with ...high efficiency and good beam quality, simultaneously. Modelling the thin disk laser behaviour shows the possible power and energy scalability.
A 1-kW CW thin disc laser Stewen, C.; Contag, K.; Larionov, M. ...
IEEE journal of selected topics in quantum electronics,
07/2000, Letnik:
6, Številka:
4
Journal Article
Recenzirano
The thin disc laser is presented as an optimal laser design for the operation of a quasi-three-level laser active medium in the high power regime with high optical efficiency. Numerical calculations ...of the laser output power show that operation with an output power up to 1 kW with an optical efficiency of 50% and more is possible at room temperature utilizing 16 absorption passes. Scaling of the output power can be realized by scaling the pumped area using one or more discs. The experimental investigations yield a maximum output power of 647 W at 51% optical efficiency for one crystal and of 1070 W with 48% optical efficiency for four crystals at a temperature of the cooling water of 15/spl deg/C.
The results for cw- and q-switched operation as well as for amplification of short (ns) and ultra-short (ps, fs) pulses demonstrate the potential of the thin disk laser design. The scaling laws for ...this laser design show that the power limit for cw-operation is far beyond 10 kW for one single disk and the energy limit is higher than 1 J from one disk in pulsed operation. First results for laser materials processing demonstrate the potential of the thin disk laser design. Finally, a short overview of the industrial realization of the thin disk laser technology will be given.
Optical in-well pumping is shown to lead to highly efficient operation of semiconductor disk-lasers using resonant absorption or using external optics. Pump radiation absorption of 70% at 940 nm is ...demonstrated for a laser emitting around 980 nm. Laser output power was 1.9 W with slope efficiencies up to 35% based on the incident power.
Im weltweiten Vergleich der Lasernationen ist Deutschland ein Schwergewicht. Bestes Beispiel sind die hierzulande erzielten Fortschritte bei diodengepumpten Festkörperlasern. Dazu gehören die ...Entwicklung von Scheiben‐ und Faserlaser. Über die Zukunft der beiden Konzepte und über die Bedeutung der Forschungsförderung für die heutige Stellung Deutschlands sprach Andreas Thoß mit Adolf Giesen und Andreas Tünnermann – den beiden führenden deutschen Wissenschaftlern im Bereich Scheiben‐ bzw. Faserlaser.
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