Working with lasers in the mid-infrared has never been straight forward. Even in the most advance laser labs, mid-infrared laser experiments are about losing most of your time in aligning and adjusting the laser parameters rather than focusing on the intended application. Until now, the lack of simple mid-IR sources has dramatically slowed down scientific advances in mid-IR spectroscopy & hyperspectral imaging, laser-matter interaction, and nonlinear optics.
In this blog, we present our most advanced scientific laser, the Femtum UltraTune 3400. This table-top, tunable ultrafast fiber laser can cover the 3000 to > 3400 nm (2940 to 3333 cm-1) spectral range within a second, without the need of a laser expert to operate it. Using this laser, applied and research scientists around the world can finally focus on mid-IR applications rather than the laser.
Easy and fast tunability in the mid-IR
The Ultratune 3400 relies on a patented in-amplifier nonlinear process to produce high average power (> 500 mW) and broad tunability in the mid-IR (3 to 3.4 µm). The fiber architecture ensures an alignment-free, reliable operation over time. As shown in the video below, Femtum’s control software allows for precise tuning of the laser to the selected central wavelength in less than a second. The laser wavelength can be tuned across the OH band (~ 3000 nm) and the CH band (~ 3300 nm) with high stability and reproducibility.
Rugged and automated mode locking
The Ultratune 3400 features a mode-locked laser oscillator that generates femtosecond pulses at 2800 nm (can be sold separately, see Ultra 2800). A reliable self-starting operation in the femtosecond regime is ensured by an integrated feedback loop technology developed by Femtum . With this automated feature, the laser is always ready for use with no warm-up time and no need for an external adjustment.
Clean, pedestal-free temporal and spectral profiles
Thanks to its nonlinear tuning mechanism, the UltraTune 3400 features a nearly perfect sech2 spectral profile. The power spectral density of the laser can be up to > 10 dBm/nm at the chosen central wavelength, which is more than 100 X higher than that of commercial mid-IR supercontinuum sources and more than 10 000 X higher than that of a black body radiation. This feature is very important for applications in sensing, microscopy and spectroscopy, where the signal-to-noise ratio and the spectral selectivity are critical.
Temporal features are also unique. The autocorrelation trace confirms pedestal-free transform-limited pulses with a nearly constant pulse duration of ~ 200 fs across the whole tuning range. These femtosecond pulses are very stable and have a peak power of > 50 kW, which is highly sufficient for exploiting efficient nonlinear interaction in mid-IR crystals or fibers.
Designed for high stability over time
The laser includes proprietary fiber components and a robust free-space architecture that ensure superior long-term stability. The image below shows a 24 h average power measurement when the laser is operated at a central wavelength of 3400 nm.
No beam pointing issue and nearly perfect gaussian beam
The Ultratune 3400 is entirely designed using optical fibers that preserve its single mode properties across the whole tuning range. The beam quality factor M2 has been evaluated to be < 1.3 based on previous measurements made at 2800 nm. Its fiber delivery cable and unique fiber collimator facilitate the delivery of the laser on a microscope, a scanner head, a processing station, or a constrained space without any beam pointing error when the laser wavelength is varied.