A 1.8 mJ, picosecond Nd:YVO4 bounce amplifier pump front-end system for high-accuracy XUV-frequency comb spectroscopy

1 mu s, providing a promising pump laser system for parametric amplification and subsequent upconversion of near-infrared frequency combs to the extreme ultraviolet (XUV). (C) 2012 by Astro, Ltd

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 4

Ramsey-comb spectroscopy: Theory and signal analysis

We recently demonstrated that the spectroscopic accuracy and resolution of optical frequency combs can be obtained from a series of Ramsey-like measurements using only two amplified frequency comb pulses at variable delays. In this work we present a comprehensive analytical framework of this Ramsey-comb method in both time and frequency domains. It is shown that as opposed to traditional forms of spectroscopy, the signal analysis can be performed purely in the time domain, based on the temporal phases of the individual Ramsey signals. We give a detailed description of the robust fitting algorithm relying solely on this phase information and discuss special features such as an insensitivity to (transition-independent) spectral line-broadening mechanisms and constant phase shifts, e.g., due to the ac Stark effect from the excitation pulses themselves. The precision and resolution of the Ramsey-comb fitting method is assessed via numerical simulations, including cases of transition-dependent broadening mechanisms and phase shifts. © 2014 American Physical Society

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. In combination with nonlinear upconversion of the amplified pulses, the presented system will potentially enable short wavelength (<100 nm), multi-transition Ramsey-frequency comb spectroscopy at the kHz-level. © 2013 Optical Society of America

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:YV

Widely tunable extreme UV frequency comb generation

Extreme UV (XUV) frequency comb generation in the wavelength range of 51 to 85nm is reported based on highorder 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%. © 2011 Optical Society of America

Direct frequency comb spectroscopy in a linear paul trap

Direct frequency comb spectroscopy is demonstrated for ions in a Paul trap for the first time. We measured a single-photon transition at 394 nm in a crystal of calcium ions with 0.5 MHz accuracy

Frequency comb metrology at PHz frequencies: Precision in the extreme ultraviolet

The capability of frequency-comb (FC) lasers to precisely measure optical frequencies is extended to the multiple-PHz domain. This frequency region, which covers the extreme ultraviolet (XUV, wavelengths shorter than 100 nm), was previously not accessible to these devices. Frequency comb generation is shown for 51-85 nm by amplification and coherent up-conversion of a pair of pulses originating from a near-infrared femtosecond FC laser. Moreover, Ramsey-like signals with up to 61% contrast are observed when the XUV comb is scanned over transitions in argon, neon and helium, resulting in an 8-fold improved determination of the ground state ionization energy of helium