Max-planck-gesellschaft Zur F&#xf6;rderung Der Wissenschaften E. V.

Ludwig-maximilians-universitaet Muenchen

Ludwig-maximilians-universitat München

Ernst Fill

Ferenc Krausz

Ioachim Pupeza

Alexander Apolonskiy

Klaus J Witte

Simon Holzberger

Walter Scrlac

Henning Carstens

Jan Kaster

Jens Rauschenberger

Liudmila Voronina

Ann-Kathrin Raab

Mihaela Zigman

Maximilian HÖGNER

Iochaim Pupeza

A method of measuring a spectral response of a biological sample (), comprises the steps generation of probe light having a primary spectrum, irradiation of the sample () with the probe light, including an interaction of the probe light and the sample (), and spectrally resolved detection of the probe light having a modified spectrum, which deviates from the primary spectrum as a result of the interaction of the probe light and the sample (), said modified spectrum being characteristic of the spectral response of the sample (), wherein the probe light comprises probe light pulses () being generated with a fs laser source device (). Furthermore, a spectroscopic measuring apparatus is described, which is configured for measuring a spectral response of a biological sample ().

Method and apparatus for measuring a spectral sample response

A method of creating difference frequency (DF) laser pulses () by difference frequency generation (DFG) comprises the steps of providing ultrashort laser pulses () having a spectral bandwidth corresponding to a Fourier limit of below 50 fs and containing first spectral components and second spectral components having larger frequencies than the first spectral components, and driving a DFG process by the ultrashort laser pulses () in an optically non-linear crystal (), wherein the DF laser pulses () are generated in the crystal () by difference frequencies between the first and second spectral components, resp., said difference frequencies comprising third spectral components being lower in frequency than the first and second spectral components, wherein at least one enhancement cavity () with resonator mirrors (Mito M) spanning a beam path () is provided and the crystal () is placed in the beam path () of the enhancement cavity (), the ultrashort laser pulses () are input coupled and coherently added in the at least one enhancement cavity (), at least one circulating ultrashort laser pulse () is created in the at least one enhancement cavity (), which drives the DFG process in the crystal () for generating the DF laser pulses (), and the at least one enhancement cavity () is adapted for recycling the at least one ultrashort laser pulse () passing through the crystal (). Furthermore, a photonic source () for creating DF laser pulses () is described, including one or more enhancement cavities.

Method and device for cavity-enhanced broadband intrapulse difference frequency generation

An enhancement resonator () being configured for generating intra-resonator laser light () by coherent superposition of input laser light, comprises at least three resonator mirrors () spanning a ring resonator path in one common resonator plane, said resonator path being free of a laser light amplifying medium, wherein the at least three resonator mirrors () include at least two toroidal mirrors and/or at least one cylindrical mirror. Furthermore, a laser device () comprising the enhancement resonator () and a method of generating intra-resonator laser light () are described.

Enhancement resonator including non-spherical mirrors

A method of generating intra-resonator laser light () comprises the steps of coupling input laser light (), e. g. laser pulse or continuous-wave light, into an enhancement resonator (), which comprises at least two curved resonator mirrors () and which is free of a laser light amplifying medium, said at least two curved resonator mirrors () being consecutively arranged and spanning at least one resonator path with a predetermined resonator length (Lres), wherein said at least two curved resonator mirrors () providing at least two pairs of consecutive curved resonator mirrors which are serially coupled along said at least one resonator path, and coherent addition of the input laser light () in the enhancement resonator so that the intra-resonator laser light () is formed, wherein said at least two pairs of consecutive curved resonator mirrors each have a detuned concentric configuration, which deviates from a concentric configuration with regard to at least one of a distance between the curved mirrors. and an angle of incidence on the curved mirror surfaces. Furthermore, an enhancement resonator (), in particular being configured for generating intra-resonator laser light (), a laser device () including the enhancement resonator device () and applications of the enhancement resonator device () are described.

Method of generating enhanced intra-resonator laser light, enhancement resonator and laser device

The pulse duration of an iodine laser is adjusted between 400 ps and 20 ns primarily by changing the resonator length in the range of about 2 cm to about 100 cm and secondarily by the ratio of excitation energy to threshold energy of the laser. Iodine laser pulses without pre-pulse and substructure are achieved in that the gas pressure of the laser gas of the iodine laser is adapted to the resonator length in order to limit the band width of the amplification and thus the band width of the pulse to be produced. The longer are the laser pulses to be produced the lower is the pressure chosen. A prerequisite for the above results is that the excitation of the iodine laser occurs extremely rapidly. This is advantageously achieved by photo-dissociation of a perfluoroalkyl iodide as CF.sub.3 I by means of laser providing sufficiently short output pumping pulses, e.g. an excimer laser, as a KrF laser or XeCl laser or a frequency-multiplied Nd-glass or Nd-YAG laser, or a N.sub.2 laser (in combination with t-C.sub.4 F.sub.9 I as laser medium). In addition to the substantial advantage of the easy variability of the pulse duration the method additionally has a number of further advantages, namely pre-pulse-free rise of the laser pulse up to the maximum amplitude; exchange of the laser medium between two pulses is not necessary at pulse repetition rates below about 1 hertz; high pulse repetition rates obtainable with laser gas regeneration; switching elements for isolating a laser oscillator from a subsequent amplifier cascade for the purpose of avoiding parasitic oscillations are not as critical as with flashlamp-pumped lasers.

Method and apparatus for the production of pre-pulse-free, smooth laser

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Garching, Germany

Ernst Fill