The new laser uses OPCPA
technology to provide mid-infrared femtosecond pulses at 100 kHz repetition rate. For Artemis, the mid-infrared will enable the generation of higher photon energy XUV pulses and the higher repetition rate allows smaller samples to be studied. For Ultra, the appeal is the ability to provide broader spectral coverage at high repetition rates, for faster data acquisition, and more efficient generation of mid- to far-IR pulses.
The smaller of the two labs holds our two laser systems, while the larger lab holds three parallel XUV beamlines, and IR spectroscopy stations for Ultra. A custom-built external plant room holds chillers, cryo-compressors and backing pumps to minimise the noise levels in the lab.
The new Artemis labs, showing the ARPES and AMO end-stations (left and centre respectively). The imaging beamline is nearest t the camera, and the 1kHz monochromatised beamline is behind it.
100 kHz IR laser
The new laser system is a 100 kHz OPCPA system from Fastlite. The system has several outputs: 170 µJ at 1700 nm and 60 µJ at 3000 nm in < 50 fs pulses at fixed wavelengths for HHG, as well as a rapidly tuneable mode with slightly lower energy, which is more suitable for IR spectroscopy experiments. The laser system is pumped by a 200 W Yb:YAG system from Trumpf Scientific, based on an industrial micro-machining system.
100 kHz OPCPA system in the new laser lab.
1 kHz Ti:Sapphire laser
The existing Artemis 1 kHz RedDragon laser
has been upgraded with a third amplifier stage to provide 2 x 8 mJ pulses. This will enable us to offer HHG with second or third harmonic drive in conjunction with tuneable outputs from the Topas OPA system, or to further amplify the output of the OPA or hollow fibre.
1 kHz Ti:Sapphire system fully re-installed in the new laser lab.
A new XUV beamline
is being built for the 100 kHz laser system. This will include a flat-field spectrometer and a monochromator. The time-resolved ARPES
experiments will be the first to move to this new beamline.
Start of assembly of 100 kHz XUV beamline.
IR spectroscopy stations
Ultra will develop IR spectroscopy stations, to allow us to initially evaluate the performance of the stable, broadband mid-IR (> 4 µm) output of the new system. As well as the appeal of using such a source for ultrafast IR spectroscopy, the narrowband (~ 20 cm-1) pump laser opens up new opportunities in ultrafast Raman and unique hybrid narrowband/broadband capability, such as surface sum frequency generation and multidimensional spectroscopy techniques (e.g. electronic-vibrational-vibrational).
The 100 kHz laser system has met specifications at the factory and has been installed in the new laser labs. We are now working with remote support from the laser engineers to learn how to run it and go through site acceptance tests. The 1 kHz laser is up and running, and we have run our first user experiment with remote user access. We are now re-commissioning the 1 kHz monochromatised beamline, and assembling the 100 kHz beamline.
We have reduced numbers of staff working in the labs at the moment, but are continuing to install equipment and prepare for user access. We expect to run experiments through 2021 with smaller user teams on-site and more remote support.
The first user experiment in the new Artemis labs in Oct 2020. Our first user was former Artemis team member Cephise Cacho, now at Diamond. The rest of the team participated remotely from France. Beamline scientists were Charlotte Sanders (pictured) and Yu Zhang.