Simas Melnikas, a physicist at the FTMC Department of Laser Technologies, has been awarded a Doctor of Technology degree. He defended his thesis "Investigation of dependence of Bragg and chirped mirrors design to spectral parameters and optical resistance" (scientific advisor: Dr. Ramutis Drazdys).
Congratulations to the colleague and best wishes for further success!
According to the author, the technology has advanced rapidly since the invention of the laser in the 1960s, with an increasing focus on powerful short-pulse lasers. Their use opens up new opportunities in fields such as attosecond physics (which won the Nobel Prize in Physics in 2023), laser particle acceleration, nuclear research and more. In addition, increasingly powerful lasers are being produced for industrial, medical and other applications that are important to us all.
These advances and increasingly powerful lasers are placing greater demands on the quality of the optical elements they use - and on their resistance to intense laser radiation.
Particularly important here are so-called chirped mirrors, which not only reflect the laser light but also help to maintain and control the light pulses. This is a challenging job, given that the femtosecond pulses for which chirped mirrors are used are almost a quadrillion (one with 15 zeros) times shorter per second.
According to the physicist, without better chirped mirrors there will be no improved powerful lasers.
(PhD defence of Simas Melnikas. Photo: FTMC)
"My work has focused on parameters of chirped mirrors such as light absorption and resistance to intense laser radiation. These parameters partly determine how powerful lasers can be developed and used.
We could compare chirped mirrors to the mirrors we use in our everyday lives. The latter absorb about 10-15% of the light, while the rest is reflected. If you were to put such a mirror in a laser system, it would be damaged - because it would absorb too much intense light, overheat and break.
This requires reducing absorption and optimising the so-called laser damage threshold. For this purpose, we are developing specific mirrors made up of many thin layers, more than 30 of them," says the new PhD.
FTMC information