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We present a new method to obtain long-term stable phase-conjugate feedback (pcf) with a photorefractive crystal for a mode-locked semiconductor laser. The phase-conjugate mirror is a barium titanate crystal in a self-pumped internal reflection configuration, and the laser is a visible, antireflection-coated AlGaInP diode. We describe a new dynamic writing(More)
In the past years, femtosecond laser spectroscopy has become an important tool in nearly all areas of modern natural science due to the continuous improvement of the respective laser systems. By means of a few selected examples from different areas of condensed-matter physics we discuss some of .the most important techniques and illustrate the versatile(More)
We demonstrate the application of a type II Al(x)Ga((1-x))As/AlAs multiple quantum well as a fast saturable absorber in a hybridly mode-locked dye laser. Type II multiple quantum wells are promising for this application because of the fast recovery of the saturated absorption with picosecond or even subpicosecond time constants. We obtain almost(More)
The unique optical properties of Se2- radicals located in the cages of the sodalite structure are reported. By means of luminescence, photoluminescence excitation, and absorption spectroscopy, three different centers are identified. Two of them are Se2- anions in sites with presumably a tetrahedral Na4(4+) coordination and a Na3(3+) environment with cation(More)
The occurrence of higher-order Fourier components in an originally sinusoidal free-carrier index grating produced in CdS by interference of two picosecond light pulses is demonstrated by simultaneously monitoring the decay of the first- and second-order diffraction intensity of a transparent probe pulse. A pronounced contribution with doubled period can be(More)
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