Phase correlation of laser waves with arbitrary frequency spacing

The theoretically predicted correlation of laser phase fluctuations in Lambda-type interaction schemes is experimentally demonstrated. We show, that the mechanism of correlation in a Lambda scheme is restricted to high frequency noise components, whereas in a double-$\Lambda$ scheme, due to the laser phase locking in closed-loop interaction, it extends to all noise frequencies. In this case the correlation is weakly sensitive to coherence losses. Thus the double-Lambda scheme can be used to correlate e.m. fields with carrier frequency differences beyond the GHz regime.Comment: 4 pages, 4 figure

Ultrastable CO2 Laser Trapping of Lithium Fermions

We demonstrate an ultrastable CO2 laser trap that provides tight confinement of neutral atoms with negligible optical scattering and minimal laser-noise- induced heating. Using this method, fermionic 6Li atoms are stored in a 0.4 mK deep well with a 1/e trap lifetime of 300 sec, consistent with a background pressure of 10^(-11) Torr. To our knowledge, this is the longest storage time ever achieved with an all-optical trap, comparable to the best reported magnetic traps.Comment: 4 pages using REVTeX, 1 eps figur

Laser Machining by short and ultrashort pulses, state of the art and new opportunities in the age of the photons

An overview is given of the applications of short and ultrashort lasers in material processing. Shorter pulses reduce heat-affected damage of the material and opens new ways for nanometer accuracy. Even forty years after the development of the laser there is a lot of effort in developing new and better performing lasers. The driving force is higher accuracy at reasonable cost, which is realised by compact systems delivering short laser pulses of high beam quality. Another trend is the shift towards shorter wavelengths, which are better absorbed by the material and which allows smaller feature sizes to be produced. Examples of new products, which became possible by this technique, are given. The trends in miniaturization as predicted by Moore and Taniguchi are expected to continue over the next decade too thanks to short and ultrashort laser machining techniques. After the age of steam and the age of electricity we have entered the age of photons now

Variation of the Observed Widths of La I Lines with the Energy of the Upper Excited Levels, Demonstrated on Previously Unknown Energy Levels

Abstract We performed systematic laser spectroscopic investigations of La I spectral lines, using optogalvanic detection. Sixteen previously unknown even parity levels, having energies between 40,300 and 44,300 cm −1 , are reported. These levels classify altogether 67 lines, not listed in spectral tables. The new levels were found due to the observation of the depopulation of the lower levels of the excited transitions. We found a remarkable variation of the observed widths of single hyperfine structure components dependent on the energy of the upper excited levels. Some levels having energies higher than 43,000 cm −1 appear to have a very high ionization probability

Laser induced fluorescence and optogalvanic spectroscopy applied to find previously unknown energy levels of La I and studies of their Zeeman structure

After the excitation of the La-Ar plasma in a hollow cathode lamp we observed in optogalvanic spectra a number of atomic lines that could not be interpreted as transitions between already known La energy levels. Using the laser induced fluorescence (LIF) method and computer simulations of the hyperfine structure patterns, we derived 14 unknown La levels, all with even parity, in the energy range between 40 877 cm(-1) and 43 485 cm(-1). The existence of these levels was then confirmed by excitations from other known lower levels. We performed also investigations of the Zeeman structure of some of these lines in order to verify the J values of newly found levels and to determine their g(J) factors. (C) 2017 Elsevier Ltd. All rights reserved