R.T. Zinkstok

A source of 2 terawatt, 2.7 cycle laser pulses based on noncollinear optical parametric chirped pulse amplification

We demonstrate a noncollinear optical parametric chirped pulse amplifier system that produces 7.6 fs pulses with a peak power of 2 terawatt at 30 Hz repetition rate. Using an ultra-broadband Ti:Sapphire seed oscillator and grating-based stretching and compression combined with an LCD phase-shaper, we amplify a 310 nm wide spectrum with a total gain of 3x10(7), and compress it within 5% of its Fourier limit. The total integrated parametric fluorescence is kept below 0.2%, leading to a pre-pulse contrast of 2 x10(-8) on picosecond timescales.

Generation of few-cycle terawatt light pulses using optical parametric chirped pulse amplification

We demonstrate the generation of 9.8+/-0.3 fs laser pulses with a peak power exceeding one terawatt at 30 Hz repetition rate, using optical parametric chirped pulse amplification. The amplifier is pumped by 140 mJ, 60 ps pulses at 532 nm, and amplifies seed pulses from a Ti:Sapphire oscillator to 23 mJ/pulse, resulting in 10.5 mJ/pulse after compression while amplified fluorescence is kept below 1%. We employ grating-based stretching and compression in combination with an LCD phase-shaper, allowing compression close to the Fourier limit of 9.3 fs.

High-power parametric amplification of 11.8-fs laser pulses with carrier-envelope phase control

Phase-stable parametric chirped-pulse amplification of ultrashort pulses from a carrier-envelope phase-stabilized mode-locked Ti:sapphire oscillator (11.0 fs) to 0.25 mJ/pulse at 1 kHz is demonstrated. Compression with a grating compressor and a LCD shaper yields near-Fourier-limited 11.8-fs pulses with an energy of 0.12 mJ. The amplifier is pumped by 532-nm pulses from a synchronized mode-locked laser, Nd:YAG amplifier system. This approach is shown to be promising for the next generation of ultrafast amplifiers aimed at producing terawatt-level phase-controlled few-cycle laser pulses.

Frequency metrology on the EF (1)Sigma(+)(g)<- X (1)Sigma(+)(g)(0,0) transition in H2, HD, and D2

We present a frequency metrology study on the lowest rotational levels of the hydrogen EF Σg+1 ←X Σg+1 (0,0) two-photon transition near 202 nm. For this purpose, the fourth harmonic of an injection-seeded titanium:sapphire pulsed oscillator is employed in a Doppler-free REMPI-detection scheme on a molecular beam of hydrogen. A frequency comb laser is used to perform the absolute frequency calibration on the continuous-wave (CW) laser that injection-seeds the oscillator. Chirp-induced frequency differences between the output of the pulsed oscillator and the seeding light are monitored on-line, while possible systematic shifts related to the AC-Stark and Doppler effects are addressed in detail. The transition frequencies of the Q (0) to Q (2) lines in H2 and D2, and the Q (0) and Q (1) lines in HD are determined with an absolute accuracy at the 10-9 level.

Phase stability of terawatt-class ultrabroadband parametric amplification

The phase stability of broadband (280 nm bandwidth) terawatt-class parametric amplification was measured, for the first time to our knowledge, with a combination of spatial and spectral interferometry. Measurements at four different wavelengths from 750 to 900 nm were performed in combination with numerical modeling. The phase stability is better than 1/23 rms of an optical cycle for all the measured wavelengths, depending on the phase-matching conditions in the amplifier.

Third-harmonic generation of a continuous-wave Ti:Sapphire laser in external resonant cavities

An all-solid-state tunable continuous-wave (cw) laser operating near 272 nm with a bandwidth Γ≈3 MHz has been developed. The third harmonic of light from a single-cw Ti:Sapphire laser has been generated using two external enhancement cavities. An output power of 175 mW has been produced, corresponding to an overall conversion efficiency of 8%.

Hyperfine structure and isotope shift of transitions in Yb I using UV and deep-UV cw laser light and the angular distribution of fluorescence radiation

Using the third harmonic of a cw titanium:sapphire laser, the hyperfine structure (HFS) and isotope shift (IS) of three deep-UV transitions of neutral Yb have been measured for the first time. By exploiting the angular distribution of fluorescence radiation, accurate and complete results are obtained for the HFS and IS of the 398.8 nm transition of Yb. From the measured data, normal and specific mass shift as well as field shift values for all transitions considered have been derived.

Demonstration of frequency comb laser spectroscopy in the vacuum-ultraviolet

High-resolution spectroscopy at 125 nm is performed on xenon, using amplified frequency comb pulse trains that are upconverted in a gas cell. This technique enables spectroscopy with sub-MHz accuracy in the vacuum-ultraviolet.

Generation of terawatt sub-8 fs laser pulses using noncollinear optical parametric chirped pulse amplification

Here we present a noncollinear optical parametric chirped pulse amplification (NOPCPA) system that produces 7.6 femtosecond pulses with a peak power exceeding 2 TW at a repetition rate of 30 Hz.

Frequency comb laser spectroscopy at vacuum-ultraviolet wavelengths and beyond

An alternative technique for precision spectroscopy, that is rapidly gaining interest, is direct excitation of atomic transitions with a train of pulses from a frequency comb laser. As the high peak intensity of such ultrashort pulses allows efficient upconversion of an infrared frequency comb output to higher frequencies, it seems very promising for extending high-resolution spectroscopy to the VUV and XUV spectral region.