81 research outputs found
Mid-Infrared ultra-high-Q resonators based on fluoride crystalline materials
Decades ago, the losses of glasses in the near infrared (near-IR) were
investigated in views of developments for optical telecommunications. Today,
properties in the mid-infrared (mid-IR) are of interest for molecular
spectroscopy applications. In particular, high-sensitivity spectroscopic
techniques based on high-finesse mid-IR cavities hold high promise for medical
applications. Due to exceptional purity and low losses, whispering gallery mode
microresonators based on polished alkaline earth metal fluoride crystals (i.e
the family, where X Ca, Mg, Ba, Sr,...) have attained
ultra-high quality (Q) factor resonances (Q10) in the near-IR and
visible spectral ranges. Here we report for the first time ultra-high Q factors
in the mid-IR using crystalline microresonators. Using an uncoated chalcogenide
(ChG) tapered fiber, light from a continuous wave quantum cascade laser (QCL)
is efficiently coupled to several crystalline microresonators at 4.4 m
wavelength. We measure the optical Q factor of fluoride crystals in the mid-IR
using cavity ringdown technique. We observe that
microresonators feature quality factors that are very close to the fundamental
absorption limit, as caused by the crystal's multiphonon absorption
(Q10), in contrast to near-IR measurements far away from these
fundamental limits. Due to lower multiphonon absorption in and
, we show that ultra-high quality factors of Q 1.4
can be reached at 4.4 m. This corresponds to an optical
finesse of 4 10, the highest value achieved for any
type of mid-IR resonator to date, and a more than 10-fold improvement over the
state-of-the-art. Such compact ultra-high Q crystalline microresonators provide
a route for narrow linewidth frequency-stabilized QCL or mid-IR Kerr comb
generation.Comment: C. Lecaplain and C. Javerzac-Galy contributed equally to this wor
Dynamics of the transition from polarization disorder to antiphase polarization domains in vector fiber lasers
We demonstrate that nonlinear polarization coupling in a fiber ring laser without polarization selective elements,
subject to the effects of average anomalous dispersion, Kerr effect and nonlinear gain saturation, leads
to the anti-synchronization of spatio-temporal chaos into ordered laminar states of orthogonal polarization temporal
domains. Adjusting the polarization coupling may also lead to the generation of stable lattices of soliton
trains with high duty cycle at repetition rates of hundreds of MHz, as well as trains of coupled dark and bright
solitons
Polarization domain wall complexes in fiber lasers
International audienceWe present a simple theoretical model that explains polarization switching in fiber ring lasers operating with a normal path-averaged dispersion and a typical intermediate level of birefringence. Such polarization dynamics, based on a type of polarization-domain-wall (PDW) structures, agree qualitatively well with our experimental observations. We also stress the complex and chaotic nature of the observed polarization-switching states. This is corroborated by detailed numerical simulations that predict the buildup of consecutive and transient PDW structures at the subnanosecond scale, which are not fully resolved experimentally
Sub-80 fe dissipative soliton large-mode-area fiber laser
We report on high-energy ultrashort pulse generation from an all-normal-dispersion large-mode-area fiber laser by exploiting an efficient combination of nonlinear polarization evolution (NPE) and a semiconductor-based saturable absorber mode-locking mechanism. The watt-level laser directly emits chirped pulses with a duration of 1 ps and 163 nJ of pulse energy. These can be compressed to 77 fs, generating megawatt-level peak power. Intracavity dynamics are discussed by numerical simulation, and the intracavity pulse evolution reveals that NPE plays a key role in pulse shaping. © 2010 Optical Society of America
Stochasticity, periodicity and localized light structures in partially mode-locked fibre lasers
Physical systems with co-existence and interplay of processes featuring distinct spatio-temporal scales are found in various research areas ranging from studies of brain activity to astrophysics. The complexity of such systems makes their theoretical and experimental analysis technically and conceptually challenging. Here, we discovered that while radiation of partially mode-locked fibre lasers is stochastic and intermittent on a short time scale, it exhibits non-trivial periodicity and long-scale correlations over slow evolution from one round-trip to another. A new technique for evolution mapping of intensity autocorrelation function has enabled us to reveal a variety of localized spatio-temporal structures and to experimentally study their symbiotic co-existence with stochastic radiation. Real-time characterization of dynamical spatio-temporal regimes of laser operation is set to bring new insights into rich underlying nonlinear physics of practical active- and passive-cavity photonic systems
Femtosecond microjoule-Class ytterbium fiber lasers
We report the generation of 830 nJ energy from a mode-locked all-normal dispersion fiber laser featuring large-mode-area photonic crystal fibers. After external compression, 550 fs pulses with 1.2 MW peak power are demonstrated. © 2011 OSA
High-energy femtosecond photonic crystal fiber laser
We report the generation of high-energy high-peak power pulses in an all-normal dispersion fiber laser featuring large-mode-area photonic crystal fibers. The self-starting chirped-pulse fiber oscillator delivers 11 W of average power at 15:5 MHz repetition rate, resulting in 710 nJ of pulse energy. The output pulses are dechirped outside the cavity from 7 ps to nearly transform-limited duration of 300 fs, leading to pulse peak powers as high as 1:9 MW. Numerical simulations reveal that pulse shaping is dominated by the amplitude modulation and spectral filtering provided by a resonant semiconductor saturable absorber. © 2010 Optical Society of America
Sub-picosecond microjoule-class fiber lasers
We study the impact of the mode-locking mechanism on the performances of a microjoule-class all-normal dispersion fiber laser featuring large-mode-area photonic crystal fibers. © 2011 OSA
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