Solid state lasers and photonic devices
Research focus
The Peer review has evaluated this group as Good
The main research lines are the following: Waveguide and photonic devices. The research involves design, modelling, fabrication and characterization of optical waveguides, both active and passive, linear and nonlinear, for the realization of photonic devices. In particular the activity focuses on active waveguides in Er- and Er-Yb-doped glasses for optical amplification and on nonlinear waveguides in periodically-poled LiNbO3 for frequency conversion and add-drop functions obtained by means of cascaded ? 2 processes. Er-Yb waveguide amplifiers with high gain (4-5 dB/cm), integrated lossless splitters (1x4, 1x8 in C-band of optical communications), and frequency converters have been realized for applications to PON and WDM networks. Frequency-stabilized solid-state lasers for metrology and environmental monitoring. This research activity is focussed on design and realization of averagepower, diode-pumped solid-state lasers in the near infrared region, pursuing several goals, such as demonstration of novel active materials (Tm- Ho:BYF/KYF, Tm:BYF/KYF/LiLuF, Yb:KYF), ultra-wide tunability (wavelength tuning range up to 230 nm has been obtained with Tm:BYF laser), frequency stabilization by different locking techniques using both relative (Fabry-Perot) and absolute (atomic or molecular transitions) frequency reference (frequency stability of the order of 1 MHz over 60 min observation time with 50KHz linewidth (1ms) is routinely achieved using CO2 molecular absorption lines with the Pound-Drever technique); mode-locking operation by electrooptic and acustooptic intracavity modulation (pulse durations from 10ps to 100ps and repetition rates from 100MHz to 10GHz). Femtosecond laser micromachining of optical materials This new technique is based on non-linear absorption of femtosecond pulses in an optical transparent material, providing a local modification of the refraction index in a small volume. By suitable translation of the sample, arbitrary 3-D –geometry, buried optical waveguides can be fabricated in a single step without the use of any photolithographic process. A variety of different devices with high performance have been demonstrated for telecom 28 applications, including splitters, directional couplers and optical filters, waveguide lasers and optical amplifiers operating at 1.5 mm. We also use femtosecond pulse irradiation for material sensitising in order to strongly enhance subsequent chemical wet etching. Microfluidic channels for biomedical applications have been realized, and integration of optical waveguide and microfluidic channels on a single substrate using the same femtosecond-laser-based apparatus is a challenging approach towards new functionalities in biochemical analysis and synthesis (lab-on-a-chip). Periodic optical structures for coherent control of light This research activity is focussed on the design and fabrication of periodic optical structures, either fiber-based or waveguide-based, for coherent temporal /spatial control of light propagation. In particular, the activity includes: 1) fabrication of complex fiber Bragg gratings using the continuous writing technique for telecom applications (pulse shaping, dispersion control), slow and fast light, ultra-high resolution optical sensing; 2) design and fabrication of engineered waveguide arrays and photonic crystal structures for diffraction light control; 3) development of waveguide-based photonic structures for the observation of basic quantum dynamical effects (Bloch oscillations, quantum diffusion suppression, coherent destruction of tunnelling).
Dipartimento di afferenza
Docenti afferenti
Full Professors
Paolo Laporta
Roberta Ramponi
Orazio Svelto
Associate Professors
Stefano Longhi
Stefano Taccheo
Giulio Cerullo
Assistant Professors
Giuseppe Della Valle
Marco Marangoni