Multi-watt, multi-octave, mid-infrared femtosecond source.

Spectroscopy in the wavelength range from 2 to 11 μm (900 to 5000 cm) implies a multitude of applications in fundamental physics, chemistry, as well as environmental and life sciences. The related vibrational transitions, which all infrared-active small molecules, the most common functional groups, as well as biomolecules like proteins, lipids, nucleic acids, and carbohydrates exhibit, reveal information about molecular structure and composition. However, light sources and detectors in the mid-infrared have been inferior to those in the visible or near-infrared, in terms of power, bandwidth, and sensitivity, severely limiting the performance of infrared experimental techniques.

Synthesis, fabrication and characterization of a highly-dispersive mirrors for the 2 µm spectral range.

We report a challenging design, fabrication and post-production characterization problem of a dispersive mirror supporting the spectral range from 2000 nm to 2200 nm and providing a group delay dispersion of -1000 fs. The absolute reflectance in the working range is over 99.95%.

Dispersive mirror for the mid-infrared spectral range of 9-11.5 μm.

A dispersive multilayer interference mirror with a group delay dispersion (GDD) of +1500  fs for the spectral range of 9-11.5 μm is presented. It is designed to compensate the GDD of an ultrashort light pulse gained when transmitting 1 mm of a zinc selenide substrate.

Group delay dispersion measurements in the mid-infrared spectral range of 2-20 µm.

We present two measurement devices which both allow the direct measurement of the group delay (GD) and group delay dispersion (GDD) of laser optics, covering the near- and mid-infrared (MIR) spectral range from 2 to 20 µm (500-5,000 cm). Two different kinds of devices were developed to measure the GDD of multilayer interference coatings. One is a resonant scanning interferometer (RSI) and the other is a white light interferometer (WLI).

Octave spanning wedge dispersive mirrors with low dispersion oscillations.

A novel concept for octave spanning dispersive mirrors with low spectral dispersion oscillations is presented. The key element of the so-called wedge dispersive mirror is a slightly wedged layer which is coated on a specially optimized dispersive multilayer stack by a common sputter coating process. The group delay dispersion (GDD) of a pulse reflected on a wedge dispersive mirror is nearly free of oscillations.

Broadband thin-film polarizer for 12 fs applications.

A broadband non-dispersive thin-film polarizer for ultrafast applications is presented. The polarizer has a controllable flat-phase and a high extinction ratio of 23:1 in the working bandwidth from 680 nm to 900 nm. This bandwidth allows supporting laser pulses down to 12 fs.

Linearly polarized, narrow-linewidth, and tunable Yb:YAG thin-disk laser.

We report on the design, fabrication, and implementation of grating-waveguide structures (GWS) for intracavity polarization and wavelength selection as well as wavelength tuning. The GWS discussed in this Letter is a combination of a low-index leaky-mode waveguide, a subwavelength diffraction grating, and a highly reflective mirror that was designed to operate in Littrow configuration. Using our device as the end mirror of an Yb:YAG thin-disk laser allowed the extraction of beams that exhibit an extremely narrow laser emission bandwidth of ≈25 pm FWHM and a high degree of linear polarization of 99±0.