Sub-100 ps Light Sources Based on Q-Switched Microchip Lasers
|Kustantaja||Tampere University of Technology|
|Tila||Julkaistu - 22 marraskuuta 2017|
|Nimi||Tampere University of Technology. Publication|
State-of-the-art results have been achieved on several fronts of research. First of all, in this work the ﬁrst Q-switched microchip lasers based on GaInNAs semiconductor saturable absorber was developed. Using second harmonic generation, we have achieved leading values for average power, pulse energy, and pulse duration for emission at 671 nm, and 532 nm. Using third harmonic generation we demonstrated emission at 355 nm and using frequency quadrupling we attained emission at 266 nm. Finally, in this work demonstrated the ﬁrst picosecond diamond Raman laser pumped at 532 nm with sub-100 ps Q-switched pulses. Owing to favorable combination of pulse energy and pulse duration, we attained efficient operation of the Raman laser with emission at yellow (573 nm); the output pulses were as short as 39 ps and the output power was 143 mW, corresponding to a conversion efficiency as high as 40%. In another approach, we demonstrated Raman laser operating at 1240 nm by pumping with 1064 nm Q-switched pulses. In this case, Raman conversion resulted in optical pulses with a duration of 62 ps and 246 mW average power, which were frequency doubled to 620 nm. The corresponding pulse duration and average power at 620 nm were 46 ps and 128 mW, respectively. As third approach, under intense pumping the 620 nm was also generated directly from 532 nm, with 10 mW of average power and 24 ps pulse duration, the shortest pulses achieved in this work.
The results open a new perspective to the development of practical laser sources delivering µJ-level short optical pulses. When combined with nonlinear conversion techniques, the technology platform covers an extensive wavelength range and could ﬁnd uses in a wide range of applications; for example, the 532 nm laser platform has been used successfully in time-gated Raman spectroscopy.