Active pump-seed-pulse synchronization for OPCPA with sub-2-fs residual timing jitter: erratum.

In the original manuscript, a residual RMS timing jitter below 2 fs between pump and seed pulses in the stabilized case was claimed. Following a reevaluation of the data, this was underestimated. Due to a rounding error in the calibration routine, a miscalculated calibration factor was extracted. By using a higher precision, the updated residual timing jitter amounts to 2.76 fs, or sub-3 fs. In this erratum, the calibration routine is briefly reviewed and Fig. 4, which presents the timing jitter in the stabilized and unstabilized case, is updated. All other results remain unaffected.

Thin-disk pumped optical parametric chirped pulse amplifier delivering CEP-stable multi-mJ few-cycle pulses at 6 kHz.

We present an optical parametric chirped pulse amplifier (OPCPA) delivering CEP-stable ultrashort pulses with 7 fs, high energies of more than 1.8 mJ and high average output power exceeding 10 W at a repetition rate of 6 kHz. The system is pumped by a picosecond regenerative thin-disk amplifier and exhibits an excellent long-term stability. In a proof-of-principle experiment, high harmonic generation is demonstrated in neon up to the 61st order.

CEP-stable, sub-6 fs, 300-kHz OPCPA system with more than 15 W of average power.

We report on a CEP-stable OPCPA system reaching multi-GW peak powers at 300 kHz repetition rate. It delivers 15 W of average power, over 50 µJ of compressed pulse energy and a pulse duration below 6 fs. By implementing an additional pump-seed-synchronization, the output parameters are stabilized over hours with power fluctuations of less than 1.5%.

Active pump-seed-pulse synchronization for OPCPA with sub-2-fs residual timing jitter.

Short-pulse-pumped optical parametric chirped pulse amplification (OPCPA) requires a precise temporal overlap of the interacting pulses in the nonlinear crystal to achieve stable performance. We present active synchronization of the ps-pump pulses and the broadband seed pulses used in an OPCPA system with a residual timing jitter below 2 fs. This unprecedented stability was achieved utilizing optical parametric amplification to generate the error signal, requiring less than 4 pJ of seed- and 10 µJ of pump-pulse-energy in the optical setup. The synchronization system shows excellent long-term performance and can be easily implemented in almost any OPCPA system.

Tailored surface-enhanced Raman nanopillar arrays fabricated by laser-assisted replication for biomolecular detection using organic semiconductor lasers.

Organic semiconductor distributed feedback (DFB) lasers are of interest as external or chip-integrated excitation sources in the visible spectral range for miniaturized Raman-on-chip biomolecular detection systems. However, the inherently limited excitation power of such lasers as well as oftentimes low analyte concentrations requires efficient Raman detection schemes. We present an approach using surface-enhanced Raman scattering (SERS) substrates, which has the potential to significantly improve the sensitivity of on-chip Raman detection systems. Instead of lithographically fabricated Au/Ag-coated periodic nanostructures on Si/SiO2 wafers, which can provide large SERS enhancements but are expensive and time-consuming to fabricate, we use low-cost and large-area SERS substrates made via laser-assisted nanoreplication. These substrates comprise gold-coated cyclic olefin copolymer (COC) nanopillar arrays, which show an estimated SERS enhancement factor of up to ∼ 10(7). The effect of the nanopillar diameter (60-260 nm) and interpillar spacing (10-190 nm) on the local electromagnetic field enhancement is studied by finite-difference-time-domain (FDTD) modeling. The favorable SERS detection capability of this setup is verified by using rhodamine 6G and adenosine as analytes and an organic semiconductor DFB laser with an emission wavelength of 631.4 nm as the external fiber-coupled excitation source.

Organic semiconductor distributed feedback laser pixels for lab-on-a-chip applications fabricated by laser-assisted replication.

The integration of organic semiconductor distributed feedback (DFB) laser sources into all-polymer chips is promising for biomedical or chemical analysis. However, the fabrication of DFB corrugations is often expensive and time-consuming. Here, we apply the method of laser-assisted replication using a near-infrared diode laser beam to efficiently fabricate inexpensive poly(methyl methacrylate) (PMMA) chips with spatially localized organic DFB laser pixels. This time-saving fabrication process enables a pre-defined positioning of nanoscale corrugations on the chip and a simultaneous generation of nanoscale gratings for organic edge-emitting laser pixels next to microscale waveguide structures. A single chip of size 30 mm × 30 mm can be processed within 5 min. Laser-assisted replication allows for the subsequent addition of further nanostructures without a negative impact on the existing photonic components. The minimum replication area can be defined as being as small as the diode laser beam focus spot size. To complete the fabrication process, we encapsulate the chip in PMMA using laser transmission welding.