LENS European Laboratory for Non Linear Spectroscopy

Sesto Fiorentino, Italy

LENS European Laboratory for Non Linear Spectroscopy

Sesto Fiorentino, Italy
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Cappelli F.,CNR Institute of Neuroscience | Cappelli F.,LENS European Laboratory for Non linear Spectroscopy | Galli I.,CNR Institute of Neuroscience | Galli I.,LENS European Laboratory for Non linear Spectroscopy | And 14 more authors.
Optics Letters | Year: 2012

We report on the narrowing of a room-temperature mid-IR quantum cascade laser by frequency locking it to a CO2 sub-Doppler transition obtained by polarization spectroscopy. A locking bandwidth of 250 kHz has been achieved. The laser linewidth is narrowed by more than two orders of magnitude below 1 kHz, and its absolute frequency is stabilized at the same level. © 2012 Optical Society of America.


Siciliani de Cumis M.,INRIM - Istituto Nazionale di Ricerca Metrologica | Siciliani de Cumis M.,CNR Institute of Neuroscience | Siciliani de Cumis M.,LENS European Laboratory for Non Linear Spectroscopy | Borri S.,CNR Institute of Neuroscience | And 15 more authors.
Laser and Photonics Reviews | Year: 2016

Narrow-linewidth lasers are key elements in optical metrology and spectroscopy. Spectral purity of these lasers determines accuracy of the measurements and quality of collected data. Solid state and fiber lasers are stabilized to relatively large and complex external optical cavities or narrow atomic and molecular transitions to improve their spectral purity. While this stabilization technique is rather generic, its complexity increases tremendously moving to longer wavelenghts, to the infrared (IR) range. Inherent increase of losses of optical materials at longer wavelengths hinders realization of compact, room temperature, high finesse IR cavities suitable for laser stabilization. In this paper, we report on demonstration of quantum cascade lasers stabilized to high-Q crystalline mid-IR microcavities. The lasers operating at room temperature in the 4.3-4.6 μm region have a linewidth approaching 10 kHz and are promising for on-chip mid-IR and IR spectrometers. Narrow linewidth lasers are key elements in optical metrology and spectroscopy. While stabilization of visible-to-near-IR lasers benefits of a variety of ultrastable references, its complexity increases tremendously moving to longer wavelenghts. In this paper, mid-IR quantum cascade laser stabilization to high-Q crystalline microresonators is reported, a promising method for mid-infrared metrology and on-chip infrared spectrometers. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA.


Galli I.,CNR Institute of Neuroscience | Galli I.,LENS European Laboratory for Non Linear Spectroscopy | Siciliani De Cumis M.,CNR Institute of Neuroscience | Cappelli F.,CNR Institute of Neuroscience | And 15 more authors.
Applied Physics Letters | Year: 2013

We report on the linewidth narrowing of a room-temperature mid-infrared quantum cascade laser by phase-locking to a difference-frequency-generated radiation referenced to an optical frequency comb synthesizer. A locking bandwidth of 250 kHz, with a residual rms phase-noise of 0.56 rad, has been achieved. The laser linewidth is narrowed by more than 2 orders of magnitude below 1 kHz, and its frequency is stabilized with an absolute traceability of 2 × 10 - 12. This source has allowed the measurement of the absolute frequency of a CO2 molecular transition with an uncertainty of about 1 kHz. © 2013 American Institute of Physics.


Borri S.,CNR Institute of Neuroscience | Borri S.,LENS European Laboratory for Non linear Spectroscopy | Galli I.,CNR Institute of Neuroscience | Galli I.,LENS European Laboratory for Non linear Spectroscopy | And 13 more authors.
Optics Letters | Year: 2012

A narrow-linewidth comb-linked nonlinear source is used as master radiation to injection lock a room-temperature mid-infrared quantum cascade laser (QCL). This process leads to a direct lock of the QCL to the optical frequency comb, providing the unique features of narrow linewidth, absolute frequency, higher output power, and wide modehop-free tunability. The QCL reproduces the injected radiation within more than 94%, with a reduction of the frequency-noise spectral density by 3 to 4 orders of magnitude up to about 100 kHz, and a linewidth narrowing from a few MHz to 20 kHz. © 2012 Optical Society of America.


Citroni M.,LENS European Laboratory for Non Linear Spectroscopy | Citroni M.,University of Florence | Fanetti S.,LENS European Laboratory for Non Linear Spectroscopy | Guigue B.,LENS European Laboratory for Non Linear Spectroscopy | And 10 more authors.
Optics Express | Year: 2014

An optical parametric generator and amplifier producing 15 ps pulses at wavelengths tunable around 2 μm, with energies up to 15 mJ/pulse, has been realized and characterized. The output wavelength is chosen to match a vibrational combination band of water. By measuring the induced birefringence changes we prove that a single pulse is able to completely melt samples of ice in the 10-6 cm3 volume range, both at room pressure (263 K) and at high pressure (298 K, 1 GPa) in a sapphire anvil cell. This source opens the possibility of studying melting and freezing processes by spectroscopic probes in water or water solutions in a wide range of conditions as found in natural environments. © 2014 Optical Society of America.


Borri S.,CNR Institute of Neuroscience | Borri S.,LENS European Laboratory for Non linear Spectroscopy | Bartalini S.,CNR Institute of Neuroscience | Bartalini S.,LENS European Laboratory for Non linear Spectroscopy | And 13 more authors.
2012 Conference on Lasers and Electro-Optics, CLEO 2012 | Year: 2012

A room-temperature mid-infrared QCL is injection-locked by a narrow-linewidth comb-linked nonlinear source. The QCL reproduces the injected radiation within ∼94%, with a frequency noise reduction of 3-4 orders of magnitude. © 2012 OSA.


PubMed | CNR Institute of Chemistry of organometallic Compounds, LENS European Laboratory for Non Linear Spectroscopy, Normal School of Pisa and University of Parma
Type: Journal Article | Journal: Chemphyschem : a European journal of chemical physics and physical chemistry | Year: 2016

In this work, the dynamics of electronic energy transfer (EET) in bichromophoric donor-acceptor systems, obtained by functionalizing a calix[4]arene scaffold with two dyes, was experimentally and theoretically characterized. The investigated compounds are highly versatile, due to the possibility of linking the dye molecules to the cone or partial cone structure of the calix[4]arene, which directs the two active units to the same or opposite side of the scaffold, respectively. The dynamics and efficiency of the EET process between the donor and acceptor units was investigated and discussed through a combined experimental and theoretical approach, involving ultrafast pump-probe spectroscopy and density functional theory based characterization of the energetic and spectroscopic properties of the system. Our results suggest that the external medium strongly determines the particular conformation adopted by the bichromophores, with a direct effect on the extent of excitonic coupling between the dyes and hence on the dynamics of the EET process itself.

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