Hamamatsu develops LD-pumped pulsed laser system that delivers 117J
Hamamatsu Photonics has developed technology for efficiently cooling a laser medium, and as a result has developed a laser-diode-pumped high-energy pulsed laser system that delivers an output of 117J – the world’s highest among laser-diode-pumped lasers, according to the firm.
The newly developed laser system, which operates at 1,030nm wavelength and offers 40ns pulse width, will further enhance the laser peening effect used for hardening the surfaces of metal materials in aircraft and automobiles.
The laser system will also prove a powerful assist for new laser processing applications such as laser forming for shaping metal materials and paint removal.
The system was developed by the ‘Research and Development of Next Generation Laser Processing Technology’ project, supported by the New Energy and Industrial Technology Development Organization (NEDO) – a national research and development agency in Japan.
It was presented for the first time at the International Congress on Optics & Photonics ‘OPIC 2019’ held in Pacifico Yokohama (Nishi-ku, Yokohama, Japan), at the end of April.
‘Our newly developed laser is an industrial pulsed laser system capable of boosting the pulse energy of seed light of 5J up to 117J by using two amplifiers, each of which is equipped with four pumping laser diode modules,’ explained Hamamatsu.
‘To enhance laser output energy, the laser medium must be efficiently cooled,’ the firm continued. ‘This newly developed laser has vastly improved cooling efficiency achieved via a cooling mechanism that cools both sides of the laser medium by circulating helium gas through the laser amplification chamber.’
The helium gas is maintained at a pressure of 5 atmospheres and a temperature of -100ᵒC for stable cooling. Moreover, in the optical window through which the laser passes, a material resistant to low temperature and high pressures has been employed, which also offers a structural design with high durability.
To make the laser medium store more energy with higher efficiency than conventional devices, Hamamatsu designed large-diameter ceramic discs optimised to easily absorb light, and incorporated six of these discs as the laser medium. The firm also came up with a unique amplifier design while mounting its compact yet high-power laser diode modules as pumping sources, enabling the system to be downsized to a footprint equivalent to laser-diode-pumped pulsed lasers developed overseas.
Hamamatsu plans to continue developing new laser media and cooling techniques to further boost the laser output energy and open up new laser processing applications.