Giancarlo Reali | University of Pavia (original) (raw)

Papers by Giancarlo Reali

Research paper thumbnail of Light propagation in dielectric materials

We present a pedagogic derivation of the electromagnetic field established in a dielectric materi... more We present a pedagogic derivation of the electromagnetic field established in a dielectric material by an impinging external field. We consider the problem from the point of view of the physical mechanism involved at the microscopic level. The internal field emerges when the material is thought of as an assembly of atoms in vacuum, each of them being polarized by the external incident field and by the re-radiated fields of all the other polarized atoms of the material. In this way, each atom becomes itself a source of secondary radiation that adds and interferes with all the other internal fields (including the internal extension of the externally impinging field), contributing to build up the total internal field within the dielectric material as well as the externally scattered field. This picture naturally leads to a connection between the microscopic properties of the material and its index of refraction, that describes the dielectric response to the applied electromagnetic fiel...

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Research paper thumbnail of Novel unstable resonator configuration with a self-filtering aperture: experimental characterization of the Nd:YAG loaded cavity

Applied Optics, 1985

A novel cavity design based on a confocal negative branch unstable resonator configuration is pre... more A novel cavity design based on a confocal negative branch unstable resonator configuration is presented. A proper choice for the size of the field limiting aperture, set at the common focal plane of the mirrors, results in removal of the hot spot inside the cavity and in the smoothing of the spatial profile of the oscillating mode. Application of this scheme to a pulsed Nd:YAG oscillator is thoroughly characterized in a variety of operational modes (fixed-Q, Q-switching, mode-locking). The main results are a high efficiency of energy extraction and excellent phase and amplitude profiles of the output beam, which shows real transform-limited performances.

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Research paper thumbnail of Laser Generated Ripple Patterns on Dielectrics and Intermediate Band Gap Semiconductors

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Research paper thumbnail of Reflection from dielectric materials

American Journal of Physics, 1982

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Research paper thumbnail of Efficient wavelength conversion with high-power passively Q-switched diode-pumped neodymium lasers

IEEE Journal of Quantum Electronics, 1998

Powerful CW diode-pumped Nd:YAG and Nd:YVO4 lasers Q-switched by Cr:YAG saturable absorbers demon... more Powerful CW diode-pumped Nd:YAG and Nd:YVO4 lasers Q-switched by Cr:YAG saturable absorbers demonstrate efficient (30%-60%) harmonic and parametric conversion, generating hundreds of milliwatts from ultraviolet to mid-infrared

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Research paper thumbnail of Compact Femtosecond Nd:Phosphate Prismless Oscillator Pumped by a Single-Mode 150-mW Laser Diode

Conference on Lasers and Electro-Optics/International Quantum Electronics Conference, 2009

» View Full Text: Acrobat PDF (488 KB) * * Note that full-text PDFs from conferences typically co... more » View Full Text: Acrobat PDF (488 KB) * * Note that full-text PDFs from conferences typically contain 1-3 pages of content, some or all of which might be an abstract, summary, or miscellaneous items. ... We present a compact, passively mode-locked and prismless Nd:phosphate ...

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Research paper thumbnail of Efficient generation of picosecond pulses by quasi-cw diode-pumped neodymium lasers

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Research paper thumbnail of Sistema laser pulsato ad alta energia per ricerche di fisica fondamentale: apparto laser ed elettronica di controllo

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Research paper thumbnail of 40-fs Yb3+:CaGdAlO4 laser pumped by a single-mode 350-mW laser diode

Optics Express

We report the results of the investigation on a passively mode-locked Yb(3+):CaGdAlO(4) laser, pu... more We report the results of the investigation on a passively mode-locked Yb(3+):CaGdAlO(4) laser, pumped by a single transverse mode laser diode emitting 350 mW at 980 nm. This particular pump source allows efficient pumping with a nearly TEM(00) beam and minimal thermal load, making the optimization of the mode-locking performance more straightforward than with higher-power multimode beams. Indeed, using a semiconductor saturable absorber mirror and extra-cavity dispersion compensation, pulses as short as 40 fs (31-nm spectrum) have been measured, tunable across 20 nm with 15-mW output power. Slightly longer Fourier-limited 46-fs pulses with 33 mW output power directly from the oscillator have been achieved, using a different saturable absorber mirror. Such overall performance, especially considering these are among the shortest pulses generated in diode-pumped ytterbium lasers, confirms the excellent qualities of Yb(3+):CaGdAlO(4).

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Research paper thumbnail of Diode-pumped passively mode-locked tunable Yb:CALGO solid-state laser

Journal of the Optical Society of America B

In this paper, we present a simple, compact, and efficient Yb:CALGO laser system that can produce... more In this paper, we present a simple, compact, and efficient Yb:CALGO laser system that can produce sub-100 fs pulses easily tunable over a 38 nm wide wavelength range between 1034 and 1072 nm. The laser is passively mode locked with a semiconductor saturable absorber and generates up to 90 mW output power (for 230 mW absorbed pump), using a single prism for both tuning and dispersion compensation.

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Research paper thumbnail of <title>High gain solid-state modules for picosecond pulses amplification</title>

Solid State Lasers and Amplifiers IV, and High-Power Lasers, 2010

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Research paper thumbnail of <title>Multiwavelength picosecond pulse generation with diode-pumped Nd:GAGG and Nd:LGGG lasers</title>

Solid State Lasers and Amplifiers IV, and High-Power Lasers, 2010

Laser operation near 1.06 mum by diode-pumped Nd:(LuxGd1-x)3Ga5O12 (Nd:LGGG, with x = 0.1) and Gd... more Laser operation near 1.06 mum by diode-pumped Nd:(LuxGd1-x)3Ga5O12 (Nd:LGGG, with x = 0.1) and Gd3AlxGa5-xO12 (GAGG, with x = 1) disordered crystals has been investigated. Cw oscillation with a slope efficiency as high as 61% and 230 mW output power was achieved with 400 mW absorbed power from a 1-W laser diode in Nd:LGGG. Under the same pumping conditions cw oscillation with a slope efficiency as high as 55% and 255 mW output power was achieved with 500 mW absorbed power in Nd:GAGG. Stable passive mode-locking with single- or multi-wavelength spectrum was obtained with a semiconductor saturable absorber mirror (SAM) and a single-prism, dispersion-compensated cavity with both the samples. Fourier-limited pulses with duration ~ 4-9 ps and output power ~ 40 mW were generated at three well-defined laser transitions in the range 1062-1067 nm with ND:GLGG. Two-color mode-locking regime well described by Fourier-limited synchronized pulses with duration ~ 3.7 and 5.9 ps and output power ~ 65 mW, with wavelength separation of 1.3 nm around 1062 nm was obtained with Nd:GAGG.

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Research paper thumbnail of Narrow-bandwidth, mid-infrared, seeded optical parametric generation in 90° phase-matched CdSiP2 crystal pumped by diffraction limited 500 ps pulses at 1064 nm

Optics Letters

Low-threshold, efficient optical parametric generation at ~6100 nm is demonstrated using CdSiP2 n... more Low-threshold, efficient optical parametric generation at ~6100 nm is demonstrated using CdSiP2 nonlinear crystal at 1 to 10 kHz repetition rates with relatively long 500 ps pump pulses at 1064 nm. Maximum single pulse energy of 8.7 μJ and average power of 79 mW are achieved for the idler. Seeding at the signal wavelength is employed using a distributed feedback laser diode, which enables approximately tenfold narrowing of the idler bandwidth down to less than 1 nm.

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Research paper thumbnail of Narrow-Band, Mid-Infrared, CdSiP2 Based Seeded Optical Parametric Generator Pumped by 120-ps, Single Mode 1064 nm Laser

form only given. Recently, we demonstrated extremely low threshold optical parametric generation ... more form only given. Recently, we demonstrated extremely low threshold optical parametric generation (OPG) pumping a CdSiP2 (CSP) crystal with 500-ps-long pulses from a Nd-laser system [1]. Diode laser seeding enabled narrow-band non-critical OPG operation at 1-10 kHz repetition rate with the idler at ~6100 nm. In comparison to [2], with a simpler Q-switching based pump system, a 4-fold improvement of the time-bandwidth product of the mid-IR pulses was obtained. Further reduction of this product, which was still ~5 times above the Fourier limit, is reported here. The pump laser system is a Q-switched Master Oscillator Power Amplifier (MOPA) laser. The master oscillator is a micro-chip PQS laser providing a train of single longitudinal mode, 120-ps long pulses, at 230 kHz repetition rate, with 4-mW average power. The average power is increased in a two-stage Nd:YVO4 amplifier up to 5.4 W, corresponding to a single pulse energy of ~ 24 μJ and a peak-power of about 0.2 MW at 1064 nm, with ...

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Research paper thumbnail of <title>Beam quality characterization of laser pulses by Z-scan techniques</title>

Laser Energy Distribution Profiles: Measurement and Applications, 1993

ABSTRACT A novel method for measuring the beam quality of short, powerful laser pulses is present... more ABSTRACT A novel method for measuring the beam quality of short, powerful laser pulses is presented. It is based on the Z-scan technique used to investigate the nonlinear susceptibilities of optical materials. We show that both two-photon absorption and nonlinear refraction of a nonlinear sample can be used to obtain information about the spatial quality of the pulses.

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Research paper thumbnail of <title>Diode-pumped solid state lasers: new resonator styles for the years 2000</title>

Laser Resonators III, 2000

ABSTRACT

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Research paper thumbnail of <title>Diode-pumped all-solid state lasers: solutions for scientific, biomedical, and industrial applications</title>

Second GR-I International Conference on New Laser Technologies and Applications, 1998

ABSTRACT

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Research paper thumbnail of 80-fs Nd:silicate glass laser pumped by a single-mode 200-mW diode

Optics express, Jan 10, 2010

A Nd(3+)-doped Schott LG680 silicate glass laser was pumped with a single-mode 200-mW diode. Effi... more A Nd(3+)-doped Schott LG680 silicate glass laser was pumped with a single-mode 200-mW diode. Efficient cw operation was demonstrated with 37.5 mW output power and 36% slope efficiency. Passive mode-locking with a semiconductor saturable absorber mirror yielded 80-fs pulses with a two-prism setup. Alternatively, pulses of approximately 200-fs, tunable over the range 1058-1076 nm, were obtained with either slit-tuning or a single-prism dispersive resonator. Output powers from 6 to 14 mW have been measured.

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Research paper thumbnail of Self-focusing in CS(2) at 10.6 microm

Optics letters, 1985

We have measured the nonlinear refractive index, n(2), of CS(2) at 10.6 microm by observing the o... more We have measured the nonlinear refractive index, n(2), of CS(2) at 10.6 microm by observing the onset of whole-beam selffocusing. We find that n(2) is (2.2 +/- 0.7) x 10(-10) esu, which is over an order of magnitude larger than n(2) in the visible.

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Research paper thumbnail of Fs Spectroscopy of Phonon Emission and Absorption for A Cold Plasma in Gallium Arsenide

MRS Proceedings, 1995

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Research paper thumbnail of Light propagation in dielectric materials

We present a pedagogic derivation of the electromagnetic field established in a dielectric materi... more We present a pedagogic derivation of the electromagnetic field established in a dielectric material by an impinging external field. We consider the problem from the point of view of the physical mechanism involved at the microscopic level. The internal field emerges when the material is thought of as an assembly of atoms in vacuum, each of them being polarized by the external incident field and by the re-radiated fields of all the other polarized atoms of the material. In this way, each atom becomes itself a source of secondary radiation that adds and interferes with all the other internal fields (including the internal extension of the externally impinging field), contributing to build up the total internal field within the dielectric material as well as the externally scattered field. This picture naturally leads to a connection between the microscopic properties of the material and its index of refraction, that describes the dielectric response to the applied electromagnetic fiel...

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Research paper thumbnail of Novel unstable resonator configuration with a self-filtering aperture: experimental characterization of the Nd:YAG loaded cavity

Applied Optics, 1985

A novel cavity design based on a confocal negative branch unstable resonator configuration is pre... more A novel cavity design based on a confocal negative branch unstable resonator configuration is presented. A proper choice for the size of the field limiting aperture, set at the common focal plane of the mirrors, results in removal of the hot spot inside the cavity and in the smoothing of the spatial profile of the oscillating mode. Application of this scheme to a pulsed Nd:YAG oscillator is thoroughly characterized in a variety of operational modes (fixed-Q, Q-switching, mode-locking). The main results are a high efficiency of energy extraction and excellent phase and amplitude profiles of the output beam, which shows real transform-limited performances.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Laser Generated Ripple Patterns on Dielectrics and Intermediate Band Gap Semiconductors

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Reflection from dielectric materials

American Journal of Physics, 1982

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Efficient wavelength conversion with high-power passively Q-switched diode-pumped neodymium lasers

IEEE Journal of Quantum Electronics, 1998

Powerful CW diode-pumped Nd:YAG and Nd:YVO4 lasers Q-switched by Cr:YAG saturable absorbers demon... more Powerful CW diode-pumped Nd:YAG and Nd:YVO4 lasers Q-switched by Cr:YAG saturable absorbers demonstrate efficient (30%-60%) harmonic and parametric conversion, generating hundreds of milliwatts from ultraviolet to mid-infrared

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Research paper thumbnail of Compact Femtosecond Nd:Phosphate Prismless Oscillator Pumped by a Single-Mode 150-mW Laser Diode

Conference on Lasers and Electro-Optics/International Quantum Electronics Conference, 2009

» View Full Text: Acrobat PDF (488 KB) * * Note that full-text PDFs from conferences typically co... more » View Full Text: Acrobat PDF (488 KB) * * Note that full-text PDFs from conferences typically contain 1-3 pages of content, some or all of which might be an abstract, summary, or miscellaneous items. ... We present a compact, passively mode-locked and prismless Nd:phosphate ...

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Research paper thumbnail of Efficient generation of picosecond pulses by quasi-cw diode-pumped neodymium lasers

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Sistema laser pulsato ad alta energia per ricerche di fisica fondamentale: apparto laser ed elettronica di controllo

Bookmarks Related papers MentionsView impact

Research paper thumbnail of 40-fs Yb3+:CaGdAlO4 laser pumped by a single-mode 350-mW laser diode

Optics Express

We report the results of the investigation on a passively mode-locked Yb(3+):CaGdAlO(4) laser, pu... more We report the results of the investigation on a passively mode-locked Yb(3+):CaGdAlO(4) laser, pumped by a single transverse mode laser diode emitting 350 mW at 980 nm. This particular pump source allows efficient pumping with a nearly TEM(00) beam and minimal thermal load, making the optimization of the mode-locking performance more straightforward than with higher-power multimode beams. Indeed, using a semiconductor saturable absorber mirror and extra-cavity dispersion compensation, pulses as short as 40 fs (31-nm spectrum) have been measured, tunable across 20 nm with 15-mW output power. Slightly longer Fourier-limited 46-fs pulses with 33 mW output power directly from the oscillator have been achieved, using a different saturable absorber mirror. Such overall performance, especially considering these are among the shortest pulses generated in diode-pumped ytterbium lasers, confirms the excellent qualities of Yb(3+):CaGdAlO(4).

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Research paper thumbnail of Diode-pumped passively mode-locked tunable Yb:CALGO solid-state laser

Journal of the Optical Society of America B

In this paper, we present a simple, compact, and efficient Yb:CALGO laser system that can produce... more In this paper, we present a simple, compact, and efficient Yb:CALGO laser system that can produce sub-100 fs pulses easily tunable over a 38 nm wide wavelength range between 1034 and 1072 nm. The laser is passively mode locked with a semiconductor saturable absorber and generates up to 90 mW output power (for 230 mW absorbed pump), using a single prism for both tuning and dispersion compensation.

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Research paper thumbnail of <title>High gain solid-state modules for picosecond pulses amplification</title>

Solid State Lasers and Amplifiers IV, and High-Power Lasers, 2010

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Research paper thumbnail of <title>Multiwavelength picosecond pulse generation with diode-pumped Nd:GAGG and Nd:LGGG lasers</title>

Solid State Lasers and Amplifiers IV, and High-Power Lasers, 2010

Laser operation near 1.06 mum by diode-pumped Nd:(LuxGd1-x)3Ga5O12 (Nd:LGGG, with x = 0.1) and Gd... more Laser operation near 1.06 mum by diode-pumped Nd:(LuxGd1-x)3Ga5O12 (Nd:LGGG, with x = 0.1) and Gd3AlxGa5-xO12 (GAGG, with x = 1) disordered crystals has been investigated. Cw oscillation with a slope efficiency as high as 61% and 230 mW output power was achieved with 400 mW absorbed power from a 1-W laser diode in Nd:LGGG. Under the same pumping conditions cw oscillation with a slope efficiency as high as 55% and 255 mW output power was achieved with 500 mW absorbed power in Nd:GAGG. Stable passive mode-locking with single- or multi-wavelength spectrum was obtained with a semiconductor saturable absorber mirror (SAM) and a single-prism, dispersion-compensated cavity with both the samples. Fourier-limited pulses with duration ~ 4-9 ps and output power ~ 40 mW were generated at three well-defined laser transitions in the range 1062-1067 nm with ND:GLGG. Two-color mode-locking regime well described by Fourier-limited synchronized pulses with duration ~ 3.7 and 5.9 ps and output power ~ 65 mW, with wavelength separation of 1.3 nm around 1062 nm was obtained with Nd:GAGG.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Narrow-bandwidth, mid-infrared, seeded optical parametric generation in 90° phase-matched CdSiP2 crystal pumped by diffraction limited 500 ps pulses at 1064 nm

Optics Letters

Low-threshold, efficient optical parametric generation at ~6100 nm is demonstrated using CdSiP2 n... more Low-threshold, efficient optical parametric generation at ~6100 nm is demonstrated using CdSiP2 nonlinear crystal at 1 to 10 kHz repetition rates with relatively long 500 ps pump pulses at 1064 nm. Maximum single pulse energy of 8.7 μJ and average power of 79 mW are achieved for the idler. Seeding at the signal wavelength is employed using a distributed feedback laser diode, which enables approximately tenfold narrowing of the idler bandwidth down to less than 1 nm.

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Research paper thumbnail of Narrow-Band, Mid-Infrared, CdSiP2 Based Seeded Optical Parametric Generator Pumped by 120-ps, Single Mode 1064 nm Laser

form only given. Recently, we demonstrated extremely low threshold optical parametric generation ... more form only given. Recently, we demonstrated extremely low threshold optical parametric generation (OPG) pumping a CdSiP2 (CSP) crystal with 500-ps-long pulses from a Nd-laser system [1]. Diode laser seeding enabled narrow-band non-critical OPG operation at 1-10 kHz repetition rate with the idler at ~6100 nm. In comparison to [2], with a simpler Q-switching based pump system, a 4-fold improvement of the time-bandwidth product of the mid-IR pulses was obtained. Further reduction of this product, which was still ~5 times above the Fourier limit, is reported here. The pump laser system is a Q-switched Master Oscillator Power Amplifier (MOPA) laser. The master oscillator is a micro-chip PQS laser providing a train of single longitudinal mode, 120-ps long pulses, at 230 kHz repetition rate, with 4-mW average power. The average power is increased in a two-stage Nd:YVO4 amplifier up to 5.4 W, corresponding to a single pulse energy of ~ 24 μJ and a peak-power of about 0.2 MW at 1064 nm, with ...

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Research paper thumbnail of <title>Beam quality characterization of laser pulses by Z-scan techniques</title>

Laser Energy Distribution Profiles: Measurement and Applications, 1993

ABSTRACT A novel method for measuring the beam quality of short, powerful laser pulses is present... more ABSTRACT A novel method for measuring the beam quality of short, powerful laser pulses is presented. It is based on the Z-scan technique used to investigate the nonlinear susceptibilities of optical materials. We show that both two-photon absorption and nonlinear refraction of a nonlinear sample can be used to obtain information about the spatial quality of the pulses.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of <title>Diode-pumped solid state lasers: new resonator styles for the years 2000</title>

Laser Resonators III, 2000

ABSTRACT

Bookmarks Related papers MentionsView impact

Research paper thumbnail of <title>Diode-pumped all-solid state lasers: solutions for scientific, biomedical, and industrial applications</title>

Second GR-I International Conference on New Laser Technologies and Applications, 1998

ABSTRACT

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Research paper thumbnail of 80-fs Nd:silicate glass laser pumped by a single-mode 200-mW diode

Optics express, Jan 10, 2010

A Nd(3+)-doped Schott LG680 silicate glass laser was pumped with a single-mode 200-mW diode. Effi... more A Nd(3+)-doped Schott LG680 silicate glass laser was pumped with a single-mode 200-mW diode. Efficient cw operation was demonstrated with 37.5 mW output power and 36% slope efficiency. Passive mode-locking with a semiconductor saturable absorber mirror yielded 80-fs pulses with a two-prism setup. Alternatively, pulses of approximately 200-fs, tunable over the range 1058-1076 nm, were obtained with either slit-tuning or a single-prism dispersive resonator. Output powers from 6 to 14 mW have been measured.

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Research paper thumbnail of Self-focusing in CS(2) at 10.6 microm

Optics letters, 1985

We have measured the nonlinear refractive index, n(2), of CS(2) at 10.6 microm by observing the o... more We have measured the nonlinear refractive index, n(2), of CS(2) at 10.6 microm by observing the onset of whole-beam selffocusing. We find that n(2) is (2.2 +/- 0.7) x 10(-10) esu, which is over an order of magnitude larger than n(2) in the visible.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Fs Spectroscopy of Phonon Emission and Absorption for A Cold Plasma in Gallium Arsenide

MRS Proceedings, 1995

Bookmarks Related papers MentionsView impact