World’s first demonstration of a stable, long-term operation of a high-energy, high-repetition-rate pulsed laser

A team of researchers at the United Kingdom government agency “Science and Technology Facilities Council” (STFC) recently reported in a publication the demonstration of a stable, long-term operation with its nanosecond pulsed diode-pumped solid-state laser (DPSSL) at 10 J, 100 Hz. The optical pulse shaping solution of Exail, the “ModBox Front-End”, was used in the front-end seed source of the system.

 

In the last decades, the United Kingdom government agency “Science and Technology Facilities Council (STFC)” has invested in the development of new laser technologies through its central laser facility (CLF). It has aimed at keeping its laser capability at the international forefront until today, principally through the development of a world leading laser architecture called DiPOLE, a new high-energy, high-repetition-rate and high efficiency pulsed laser technology. DiPOLE is the first cryogenically gas cooled, diode-pumped, solid-state laser (DPSSL) system, initially conceived as a prototype. The DiPOLE laser architecture provides a scalable concept design. This complex technology was proven mature and established as a reference in the field. It relies on an innovative laser diode pumping system and a powerful cryogenic cooling system, based on intense gas bursts. It also has a multi-slab amplifier head. The DiPOLE laser system is designed for operation from 10 Hz to 100 Hz pulse repetition rate, with pulses at high-energy.

In March 2024, the STFC Central Laser Facility team demonstrated a world premiere: the stable, long-term operation of the nanosecond pulsed DPSSL. 15 ns pulses at 1029.5 nm wavelength were amplified to 10 J energy at 100 Hz pulse rate, corresponding to 1 kW average power, with 25.4% optical-to-optical efficiency. The laser was operated at this level for over 45 minutes (∼3 · 105 shots) in two separate runs with a rms energy stability of 1%. The results were published in Optics Express, a journal of OPTICA.

The DiPOLE-100Hz laser design relies on Exail Modbox-FE-1030nm-40dB as a front-end seed source. The resulting output of the fiber seed source consists of few-nJ, arbitrarily shaped, pulses with duration between 1 and 100 ns at 100 Hz, delivered via a polarization-maintaining fiber. Being able to generate accurate impulsions with reliability over time is a challenge for such a demanding laser facility. Exail could meet all the requirements with its ModBox Front-End, a versatile sub-nanosecond laser pulse generation transmitter based on unparalleled LiNbO3 modulator design.

The ModBox Front-End selected to equip the DIPOLE laser systems is an industrial turnkey system, based on Exail’s unique know-how in designing and manufacturing LiNbO3 modulation solutions. The company has built up strong experience in such systems and successfully installed them in many research laboratories over the world, and in industrial companies.

Exail ModBox Front-End

 

3D rendering of the DiPOLE 100 Hz system (Mariastefania De Vido and al., Optics Express, 2024)