High-energy, high-repetition-rate picosecond pulses from a quasi-CW diode-pumped Nd:YAG system.

We report on a high-power quasi-CW pumped Nd:YAG laser system, producing 130 mJ, 64 ps pulses at 1064 nm wavelength with a repetition rate of 300 Hz. Pulses from a Nd:YVO(4) oscillator are first amplified by a regenerative amplifier to the millijoule level and then further amplified in quasi-CW diode-pumped Nd:YAG modules. Pulsed diode pumping enables a high gain at repetition rates of several hundred hertz, while keeping thermal effects manageable.

Multi-delay, phase coherent pulse pair generation for precision Ramsey-frequency comb spectroscopy.

We demonstrate the generation of phase-stable mJ-pulse pairs at programmable inter-pulse delays up to hundreds of nanoseconds. A detailed investigation of potential sources for phase shifts during the parametric amplification of the selected pulses from a Ti:Sapphire frequency comb is presented, both numerically and experimentally. It is shown that within the statistical error of the phase measurement of 10 mrad, there is no dependence of the differential phase shift over the investigated inter-pulse delay range of more than 300 ns.

Tailored pulse sequences from an 880 nm pumped Nd:YVO4 bounce amplifier.

We report on an 880 nm quasi-continuously pumped Nd:YVO4 grazing-incidence "bounce" amplifier, operating at a 300 Hz repetition rate. More than 70 dB small signal gain is achieved with a single crystal. Combined with fast programmable modulators, high-contrast and near-diffraction-limited pulse sequences at the 100 μJ level are produced and can be tailored in terms of pulse duration, amplitude, and a temporal spacing well into the microsecond range.

Widely tunable extreme UV frequency comb generation.

Extreme UV (XUV) frequency comb generation in the wavelength range of 51 to 85 nm is reported based on high-order harmonic generation of two consecutive IR frequency comb pulses that were amplified in an optical parametric chirped pulse amplifier. The versatility of the system is demonstrated by recording direct XUV frequency comb excitation signals in He, Ne, and Ar with visibilities of up to 61%.

Direct frequency-comb spectroscopy of a dipole-forbidden clock transition in trapped 40Ca+ ions.

We demonstrate direct frequency-comb (FC) spectroscopy of the dipole-forbidden 4s(2)S(1/2)-3d(2)D(5/2) transition in trapped (40)Ca(+) ions using an unamplified FC laser. The excitation is detected with nearly 100% efficiency using a shelving scheme in combination with single-ion imaging. The method demonstrated here has the potential to reach hertz-level accuracy, if a hertz-level linewidth FC is used in combination with confinement in the Lamb-Dicke regime.