Ultrafast lasers and applications

Ultrafast lasers  are key enabling tools for a number of scientific and engineering fields. While  the field of ultrafast laser science and engineering started not long after the  first laser was invented, today laser physicists and engineers are still  actively pushing the technology further in terms of pulse width, power and  spectral coverage. For example, the pulse duration of an ultrafast laser typically  defines the temporal resolution of an optical spectroscopic system. With recent  breakthrough, researchers can now access pulses down to 53 attoseconds [Nat. Commun. 8, 186 (2017)]. In  parallel, over the past two decades efforts are underway to apply ultrafast  lasers in areas with broader societal impact, such as manufacturing and health  care. In this research scope of our group, we are primarily interested in  developing high performance ultrashort pulsed lasers operating in the  long-wavelength range, for emerging communications and sensing applications. The  following are some exemplary research projects in the group.  

Broadly tunable pulsed lasers
    The wavelength tunability  of mode-locked lasers enables a great degree of application flexibility for end  users in frequency comb generation, molecular absorption line detection, and  time-resolved spectroscopy. By employing saturable absorbers with brand  bandwidth, our group demonstrated lasers featuring record tunability in a wide  spectral range. For example, by using carbon nanotube/graphene, we have shown a  combined tuning range of up to 500 nm at 2 μm. Such sources are low-cost  alternative for conventional OPO/OPA systems and have commercial potential for  a range of sensing and spectroscopy applications.

 

High  repetition-rate laser

High repetition-rate lasers operating at the eye-safe 2 μm region are essential for a number of fields such as high  capacity telecommunication and data processing.
    We have improved the repetition-rate of 2 μm mode-locked lasers by  more than one order of magnitude to 20 GHz. Furthermore, the pulse width of the  mode-locked pulses can be tuned by changing the detuning frequency and  repetition rate. Our group also firstly demonstrated a stable and highly  flexible GHz repetition-rate picosecond laser sources at 2 μm by spectrally  masked phase modulation technique. Both sources can be synchronized to a master  clock at a high repetition rate, which paves the way for high speed  mid-infrared applications.


Related  group publications:
Nature Nanotechnology 3, 738 (2008)
Nature Communications 8, 14111 (2017)
 Opt. Lett. 44, 4103 (2019)
 Opt. Lett. 44, 582 (2019)
 Opt. Lett. 43, 1503 (2018)
Appl. Phys. Lett. 101, 153107 (2012)
Appl. Phys. Lett. 98, 073106 (2011)
Appl. Phys. Lett. 97, 203106 (2010)
Opt. Express 18, 20774 (2016)
Opt. Express 26, 25769 (2018)
Opt. Express 27, 3518 (2019)

 


School of Electronic Science and Engineering, Nanjing University
163 Xianlin Avenue, 210023 Nanjing, China

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