Nonlinear absorption in lithium triborate frequency converters for high-power ultrafast lasers.

We report on an analysis of the nonlinear absorption in lithium triborate (LBO) used for second and third harmonic generation of ultrashort laser pulses at average powers in the order of kW and with sub-picosecond pulse duration. Thermographic imaging of the LBO crystals together with a simple analytical model revealed the presence of nonlinear absorption in both harmonic generation processes. Subsequent processing with a numerical model considering the nonlinear mixing, the absorption, and the heat conduction was used to estimate the absorption coefficients.

Ultrafast green thin-disk laser exceeding 1.4 kW of average power.

We present an ultrafast laser with a near-diffraction-limited beam quality delivering more than 1.4 kW of average power in the visible spectral range. The laser is based on second harmonic generation in a lithium triborate crystal of a Yb:YAG thin-disk multipass amplifier emitting more than 2 kW of average power in the infrared.

Phase-matched second-harmonic generation in a flux grown KTP crystal ridge optical waveguide.

Type II second-harmonic generation was performed in a 15.8-mm-long KTiOPO (KTP) micrometric ridge waveguide with an average transversal section of 38  μm. Theoretical predictions are compared with experiments.

Highly-efficient continuous-wave intra-cavity frequency-doubled Yb:LuAG thin-disk laser with 1 kW of output power.

We report on the generation of continuous-wave, intra-cavity frequency-doubled, multi-mode laser radiation in an Yb:LuAG thin-disk laser. Output powers of up to 1 kW at a wavelength of 515 nm were achieved at an unprecedented optical efficiency of 51.6% with respect to the pumping power of the thin-disk laser.

Wavelength dispersion measurement of electro-optic coefficients in the range of 520 to 930 nm in rubidium titanyl phosphate using spectral interferometry.

Rubidium titanyl phosphate (RTP) is widely used for electro-optical applications at low switching voltages. RTP is nonhygroscopic and does not induce piezoelectric ringing up to the megahertz range. It has large electro-optic (EO) coefficients and a high damage threshold.