Self-mode-locked Cr3+:LiCaAlF6 laser

Feed-forward stabilization of a single-frequency, diode-pumped Pr:YLF-Cr:LiCAF laser operating at 813.42 nm

We introduce a simple and compact diode-pumped Pr:YLF-Cr:LiCAF laser, operating at 813.42 nm and providing a 130-mW, single-frequency output tunable over a 3-GHz range. The laser has a short-term intrinsic linewidth estimated to be 700 Hz (β-separation method), while exhibiting a free-running wavelength stability of below 1 pm in one hour. Using a feed-forward technique we demonstrate the integration of the laser output into a fully stabilized, 1-GHz Ti:sapphire laser frequency comb, resulting in a heterodyne beat note between the laser and the comb with a bandwidth of 65 kHz. Combining feed-forward control with a low-bandwidth servo feedback loop permits stable long-term locking with an rms beat note variation of 15 kHz over 2 minutes. This performance makes the laser a potential candidate for the lattice laser in a ⁸⁷Sr optical lattice clock.

Compact efficient multi-GHz Kerr-lens mode-locked diode-pumped Nd:YVO4 laser

We demonstrate the compact efficient multi-GHz Kerr-lens mode locking in a diode-pumped Nd:YVO(4) laser with a simple linear cavity without the need of any additional components. Experimental results reveal that the laser system can be characterized in stable single-pulse and multiple-pulse mode-locked operations. With a pump power of 2.5 W, the compact laser cavity produces average output powers greater than 0.8 W with a pulse width less than 10 ps in the range of 2-6 GHz.

Analytic expressions for the fourth- and the fifth-order dispersions of crossed prisms pairs

In case of tunable ultrashort-pulse lasers, besides the prism material, separation, and insertion, one may choose the central wavelength providing a better high-order dispersion compensation. Because of errors that accumulate in numerical iterations, the analytic approach may be preferable for high-order dispersion examination. Analytic expressions for the fourth- and the fifth-order dispersions of crossed prisms pairs, both at arbitrary and Brewster-angle incidences are presented. Examples are given for e-sapphire slabs and for one or two pairs of fused-silica prisms. Results are shown providing compensation of both the second- and the third-order dispersions, by keeping as low as possible the higher-order ones.

Cavity-dumped femtosecond Kerr-lens mode locking in a chromium-doped forsterite laser

We report the operation of a cavity-dumped self-mode-locked chromium-doped forsterite laser with pulse energies exceeding 30 nJ and pulse durations as short as 54 fs (FWHM) at 1260 nm. By frequency doubling in a beta-barium borate crystal, pulse energies as high as 3 nJ and pulse durations as short as 49 fs (FWHM) at 630 nm were generated. The high stability and ultrashort pulse widths with a variable repetition rate in both the infrared (1260 nm) and the red (630 nm) make this system an attractive light source for ultrafast spectroscopy.

Properties of Cr:LiSrAIF(6) crystals for laser operation

We have performed several physical and optical measurements on the Cr:LiSAF (LiSrAlF(6)) laser material that are relevant to its laser performance, including thermal and mechanical properties, water durabilities, and Auger upconversion constants. The expansion coefficient, Young's modulus, fracture toughness, thermal conductivity, and heat capacity are all used to determine an overall thermomechanical figure of merit for the crystal. An investigation of the water durability suggests that the cooling solution should be maintained at pH = 7 to ameliorate problems associated with water dissolution. The Auger constant was found to become much more significant at higher Cr doping, in which excited-state migration leads to a substantial increase in the upconversion rate. We propose a design for a 50-W Cr:LiSAF laser system that is based on a detailed knowledge of all the relevant material parameters.