Mr Flavio Fusari - Ph.D. student

Flavio obtained his first degree from the University of Padova, Italy, in 2006 in Electronic Engineering with a specialization in Microelectronics. This degree was run as a single cycle BSc plus MSc degree. He joined the Optoelectronics and THz Laboratory at the University of Essex in 2005 through the Erasmus programme to develop his final year project : "Enhanced control of a pump-probe system" (Abstract) under the supervision of Dr. Anthony J. Vickers. He has joined the W-SQUAD, Ultra-Short Pulse Laser Research Group in January 2007 pursuing his interests in photonics. Flavio is involved in spectroscopy and laser characterization of new crystalline materials and glasses doped with rare earths ions for ultrashort pulse generation in near and mid infrared region.

Recent publications

F. Fusari, S. Vetter, A. A. Lagatsky, B. Richards, S. Calvez, A. Jha, M. D. Dawson, W. Sibbett, and C. T. A. Brown
Tunable laser operation of a Tm3+-doped tellurite glass laser near 2 µm pumped by a 1211 nm semiconductor disk laser
Optical Materials, ( 2010 ), in Press.

X. Han, F. Fusari, M. D. Serrano, A. A. Lagatsky, J. M. Cano-Torres, C. T. A. Brown, C. Zaldo, and W. Sibbett
Continuous-wave laser operation of Tm and Ho co-doped NaY(WO4)2 and NaLu(WO4)2 crystals
Optics Express, Vol. 18, 6, pp. 5413–5419, (2010)

B. Richards, A. Jha, Y. Tsang, D. Binks, J. Lousteau, F. Fusari, A. Lagatsky, C. Brown, W. Sibbett
"Tellurite glass lasers operating close to 2 μm"
Laser Physics Letters (currently online only).
Abstract: Recent work in the area of Tm3+ and Ho3+-doped tellurite fibre and bulk glass lasers operating close to 2 μm is reviewed. Spectroscopic properties of these doped glasses are discussed as well as the relevant pump schemes and energy transfer processes involved. Results of continuous wave (CW) and Q-switched Tm3+ and Ho3+-doped tellurite fibre lasers are then presented and discussed. Finally, the results of tellurite bulk glass laser experiments conducted to date are reported.

A. A. Lagatsky, F. Fusari, S. Calvez, S. V. Kurilchik, V. E. Kisel, N. V. Kuleshov, M. D. Dawson, C. T. A. Brown, and W. Sibbett
"Femtosecond pulse operation of a Tm,Ho-codoped crystalline laser near 2 μm"
Optics Letters, 35, (2), pp. 172, (2010).
We demonstrate, for the first time to our knowledge, femtosecond-regime mode locking of a Tm,Ho-codoped crystalline laser operating in the 2 μm spectral region. Transform-limited 570 fs pulses were generated at 2055 nm by a Tm,Ho:KY(WO4)2 laser that produced an average output power of 130 mW at a pulse repetition frequency of 118 MHz. Mode locking was achieved using an ion-implanted InGaAsSb quantum-well-based semiconductor saturable absorber mirror.

A. A. Lagatsky, F. Fusari, S. V. Kurilchik, V. E. Kisel, A. S. Yasukevich, N. V. Kuleshov, A. A. Pavlyuk, C. T. A. Brown, W. Sibbett
"Optical spectroscopy and efficient continuous-wave operation near 2 μm for a Tm,Ho:KYW laser crystal"
Applied Physics B - Lasers and Optics, 97, pp. 321-326, (2009).
Abstract: The growth, spectroscopy and lasing performance of a novel Tm,Ho:KY(WO4)2 crystal are reported. The peak emission cross-section of the Ho3+ 5I7→5I8 transition and lifetime of the 5I7 excited state were determined to be 4.8×10−20 cm2 and 1.8 ms, respectively, in a spectral range at around 2060 nm. Using a Ti:sapphire laser as a pump source at 802 nm, a maximum slope efficiency of up to 44% has been achieved with a corresponding output power of 460 mW at 2056 nm during continuous-wave operation of a Tm,Ho:KY(WO4)2 laser at room temperature. A tuning range of 1890–2080 nm has been demonstrated.

A. A. Lagatsky, F. Fusari, S. Calvez, J. A. Gupta, V. E. Kisel, N. V. Kuleshov, C. T. A. Brown, M. D. Dawson, W. Sibbett
"Passive mode locking of a Tm,Ho:KY(WO4)2 laser around 2 μm"
Optics Letters, 34, (17), pp. 2587-2589 (2009).
Abstract: We report the first demonstration, to our knowledge, of passive mode locking in a Tm3+, Ho3+-codoped KY(WO4)2 laser operating in the 2000-2060 nm spectral region. An InGaAsSb-based quantum well semiconductor saturable absorber mirror is used for the initiation and stabilization of the ultrashort pulse generation. Pulses as short as 3.3 ps were generated at 2057 nm with average output powers up to 315 mW at a pulse repetition frequency of 132 MHz for 1.15 W of absorbed pump power at 802 nm from a Ti:sapphire laser.

F. Fusari, A. A. Lagatsky, B. Richards, A. Jha, W. Sibbett, and C. T. Brown
"Spectroscopic and lasing performance of Tm3+-doped bulk TZN and TZNG tellurite glasses operating around 1.9 μm "
Optics Express, 16, (23): 19146–19151 (2008).

Abstract: We report spectroscopic and bulk laser performance characteristics for Tm3+-doped tellurite glasses when used as gain media operating around 1.9 µm. Two glass hosts studied are TZN and TZNG and their performances have been compared. In each case, well-characterized cw laser performance was obtained and this has been related to detailed spectroscopic measurements of the important lasing parameters of the laser transitions around 1900 nm when pumped at 793 nm. The maximum output power achieved was 124 mW from the TZNG sample with an associated slope efficiency of 28 % with a tuning range of 135 nm. Efficiency and loss analyses yielded a calculated maximum attainable efficiency of 48 % in Tm3+:TZN compared to 28 % for the TZNG host.

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