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.

Femtum UltraTune series

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.

Ultratune 3400 wide tunability

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.

Typical mid-IR spectra with a spectral bandwidth (FWHM) exceeding 40 nm

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.

Typical autocorrelation trace for pulses at 3200 nm. The estimated duration is 214 fs.

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.

Long-term average power measurement at 3400 nm. The relative standard deviation in average power is estimated at 0.25% for 24h of operation.

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.

Beam profile on a thermal card (Qualitative only)

For more information about our lasers, please see the product page or contact us.