A Great Week for DiPOLE
20 Aug 2020
- Helen Towrie



World Record output energy of 150J and second harmonic conversion efficiency of 77% in green wavelength.


​​The DiPOLE lab​


Recently, the CALTA team at the CLF have utilised  DIPOLE concept to demonstrate record-breaking output laser energy of 150J, 1Hz in the D100X laser (build for XFEL high energy density science experiments), moreover, utilising a small-scale prototype laser, they also demonstrated stable long-term energy stability of second harmonic generation (SHG) in green with 77% conversion efficiency.   

For a number of years we at the CLF have been developing our line of “next generation" lasers which focus on real world applications for industry. Such examples of this include laser shock peening and advanced materials processing.

The laser systems, based on the DiPOLE Concept, are built off our unique understanding gained from over 40 years of experience as a laser facility. The DiPOLE laser features include scalable diode pumped cryogenic gas cooled, multi-slab amplifier head with a compact design. These combined traits allow for a high-energy and high-repetition pulse rate suitable for industry use.

So far, we have created 3 versions of the laser system; a small-scale prototype which resides at RAL, DiPOLE100 installed in Prague as part of Hilase facility, and D100X, which has recently been shipped to Hamburg, Germany where it will be utilised for high energy density (HED) experiments at XFEL facility.

The small scale prototype RAL-based DiPOLE laser has proven itself extremely useful for developing new concepts, making discoveries and  has been the used extensively for testing new frontiers, like second harmonic generation (SHG) into visible (green) wavelength. This is pivotal in the development of ultra-high intensity femtosecond lasers. 

Recently, the first of the novel breakthroughs performed by D100X laser system was the demonstration of world's highest output energy of 150J ever recorded by a diode-pumped solid state laser (DPSSL) system.   

Dr Saumyabrata Banerjee said about the world record, “Achieving both high energy and high repetition rate laser system has been a bottleneck in the development of advanced applications like multi-Hz Petawatt lasers, high rep-rate secondary radiation sources (like x-rays, mono-energetic electron and proton beams) for imaging and therapy,  and high-energy density experiments. This demonstration of 100J, 10Hz and subsequently 150J, 1Hz is more than just beating the record for us in CLF, this will unlock the path for future developments and advanced applications with immense societal impact."

The second promising feat achieved by the small-scale prototype laser,  was the demonstration of stable long-term second harmonic generation (SHG) with a conversion efficiency of 77%! The CALTA team have used a type-I phase–matched lithium triborate (LBO) crystal to deliver a 515 nm pulse with energy 4.3 J from a fundamental input (1030nm) of 5.4 J at 10 Hz (54 W).

Dr. Jonathan Phillips, the scientist leading the experiment, said, “Myself and the CALTA team are extremely pleased with this result. On top of the improved frequency conversion in the green,  stable long-term high-energy output  at a repetition-rate of 10 Hz was demonstrated. This will determine a faster route to experimental parameter space and exploring real world applications. This is achievable by the development of higher repetition rate Ti:sapphire amplifiers and optical parametric chirped pulse amplifiers (OPCPAs), for applications which include laser particle acceleration, active real time imaging and medical therapies. We aim to improve the efficiency in the green and incorporate this technique to higher energies in the future."


Read about DiPOLE's World Record output energy here: http://www.clp.ac.cn/EN/Article/OJb7029d5a57754191

Read more about DiPOLE's SHG with 77% conversion efficiency here: https://doi.org/10.1364/OL.383129


Contact: Towrie, Helen (STFC,RAL,CLF)