Recent advances in ultrafast laser and supercontinuum generation technology have enabled the development of novel types of compact fiber based ultrafast lasers and frequency combs operating above 2 microns. The first prototypes of these lasers have successfully gone through the industrial feasibility studies and are entering the market.
These sources are characterized by ultrashort pulse duration down to few optical cycles, Watt level output power, tens of nanojoules pulse energy, and up to GHz repetition rate. Important aspect of the new technology is the tunability of the laser output. The emission wavelength of the femtosecond laser is selectable by the customer in the wide spectral range, roughly from 2 to 3 um. In the case of all-fiber design, the emission wavelength could be also made electronically tunable up to 2.5 micrometres, while keeping the pulse duration in femtosecond range. Alternatively, if demanded by application, the laser can be configured as a coherent supercontinuum light source with spectrum reaching wavelengths well beyond 3 um.
The built-in tunability of femtosecond pulses, high quality frequency combs as well as the ability to produce supercontinua directly from the laser allows using these light sources in a range of new and exciting application areas in science and industry. The application areas include, but are not limited to microelectronics, photovoltaics, THz generation, confocal nonlinear microscopy and surgery, as well as environmental, oil and gas sensing.
The talk will overview the proprietary ATLA Lasers AS laser technology of the mid-infrared ultrashort pulse lasers and supercontinuum sources. Focus will be made on the specific aspects of the technology making it particularly attractive for industrial applications demanding either high quality processing or ultrahigh sensitivity measurements.
We report the solid-state Cr:ZnS laser mode-locked by CNT-based saturable absorber. The absorber was deposited on a protected silver mirror used as a high reflector mirror in a standard 250-MHz cavity with chirped mirror GDD compensation. Laser pulses with duration of 61 fs were obtained at 2.35 μm wavelength. The output power was limited at 950 mW, corresponding to the pulse energy of 3.8 nJ. We have demonstrated the longest-wavelength mid-IR CNT-mode-locked laser with record parameters, advancing the carbon nanotube mode-locking technology well beyond 2 μm into the mid-IR.
We demonstrate mid-infrared (mid-IR) supercontinuum generation with bandwidth from 2 to 2.8 μm at 20 dB below the peak in nonlinear step-index chalcogenide fiber using femtosecond mid-IR pulses directly from the oscillator. We compare the results with a supercontinuum generated in a silica-based high germanium content fiber. Supercontinuum generation occurs at 90 mW of launched average pump power that is equal to the 0.9 nJ pulse energy. The distinctive feature of the obtained supercontinuum is its stability and coherence due to the deterministic supercontinuum generation by the femtosecond pump pulses
A room-temperature Kerr-Lens modelocked (KLM) Cr:ZnS laser generates <70 fs pulses duration (about eight optical
cycles) with 5.6 nJ pulse energy and over 100 nm FWHM spectral width at 105-157 MHz repetition rates. The laser
produces 1 W average output power at 20% optical efficiency, limited by the available Er:fiber pump. For further pulse
energy scaling we also realized the chirped-pulse regime, with 0.8-2 ps pulse durations. The demonstrated applications of such mid-IR source range from extra- and intra-cavity spectroscopy to subharmonic OPO pumping. For
environmentally-protected delivery we suggest and realize duration-preserving soliton delivery in a ZBLAN fiber.
Further bandwidth increase is demonstrated by 2.0-2.8 μm supercontinuum generation in a chalcogenide fiber.