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Measurement of the third-order nonlinear optical susceptibility chi^(3) for the 1002-cm^-1 mode of benzenethiol using coherent anti-Stokes Raman scattering with continuous-wave diode lasers

Published in:
J. Raman Spectrosc., Vol. 43, No. 7, July 2012, pp. 911-916.

Summary

The components of the third-order nonlinear optical susceptibility x^(3) for the 1002-cm^?1 mode of neat benzenethiol have been measured using coherent anti-Stokes Raman scattering with continuous-wave diode pump and Stokes lasers at 785.0 and 852.0 nm, respectively. Values of 2.8±0.3 X 10^-12, 2.0±0.2 X 10^-12, and 0.8±0.1 X 10^-12 cmg^-1 s^2 were measured for the xxxx, xxyy, and xyyx components of |3x^(3)|, respectively. We have calculated these quantities using a microscopic model, reproducing the same qualitative trend. The Raman cross-section sigma RS for the 1002-cm^-1 mode of neat benzenethiol has been determined to be 3.1±0.6 X 10^-29 cm^2 per molecule. The polarization of the anti-Stokes Raman scattering was found to be parallel to that of the pump laser, which implies negligible depolarization. The Raman linewidth (full-width at half-maximum) Gamma was determined to be 2.4±0.3 cm^-1 using normal Stokes Raman scattering. The measured values of sigma RS and Gamma yield a value of 2.1±0.4 X 10^-12 cmg^-1 s^2 for the resonant component of 3x^(3). A value of 1.9±0.9 X 10^-12 cmg^-1 s^2 has been deduced for the nonresonant component of 3x^(3).
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Summary

The components of the third-order nonlinear optical susceptibility x^(3) for the 1002-cm^?1 mode of neat benzenethiol have been measured using coherent anti-Stokes Raman scattering with continuous-wave diode pump and Stokes lasers at 785.0 and 852.0 nm, respectively. Values of 2.8±0.3 X 10^-12, 2.0±0.2 X 10^-12, and 0.8±0.1 X 10^-12 cmg^-1...

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Sub-picosecond pulses at 100 W average power from a Yb:YLF chirped-pulse amplification system

Published in:
Opt. Lett., Vol. 37, No. 13, 1 July 2012, pp. 2700-2702.

Summary

We present a high-repetition-frequency, diode-pumped, and chirped-pulse amplification system operating at 106 W average output with excellent beam quality (M^2 = 1.3), based on cryogenically cooled Yb:YLF. 1 nJ seed pulses, derived from a mode-locked Ti:sapphire laser, are first amplified to 1 mJ pulse energy at 10 kHz repetition frequency in a regenerative amplifier. The second-stage, multipass amplifier increases the pulse energy to 10.6 mJ, resulting in a spectral width of 2.2 nm. The pulses are compressed to 865 fs in duration, which is 1.26 times the transform limit.
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Summary

We present a high-repetition-frequency, diode-pumped, and chirped-pulse amplification system operating at 106 W average output with excellent beam quality (M^2 = 1.3), based on cryogenically cooled Yb:YLF. 1 nJ seed pulses, derived from a mode-locked Ti:sapphire laser, are first amplified to 1 mJ pulse energy at 10 kHz repetition frequency...

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Waveguide engineering for hybrid Si/III-V lasers and amplifiers

Published in:
CLEO: Conf. on Lasers and Electro-Optics, 6-11 June 2012.

Summary

Using adiabatic tapers, hybrid silicon / III-V lasers and amplifiers are integrated with conventional thin (t = 0.25 um) silicon waveguides. Amplifiers have ~12 dB intrachip gain, and similar lasers have thresholds of 35 mA.
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Summary

Using adiabatic tapers, hybrid silicon / III-V lasers and amplifiers are integrated with conventional thin (t = 0.25 um) silicon waveguides. Amplifiers have ~12 dB intrachip gain, and similar lasers have thresholds of 35 mA.

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External cavity beam combining of 21 semiconductor lasers using SPGD

Published in:
Appl. Opt., Vol. 51, No. 11, 10 April 2012, pp. 1724-1728.

Summary

Active coherent beam combining of laser oscillators is an attractive way to achieve high output power in a diffraction limited beam. Here we describe an active beam combining system used to coherently combine 21 semiconductor laser elements with an 81% beam combining efficiency in an external cavity configuration compared with an upper limit of 90% efficiency in the particular configuration of the experiment. Our beam combining system utilizes a stochastic parallel gradient descent (SPGD) algorithm for active phase control. This work demonstrates that active beam combining is not subject to the scaling limits imposed on passive-phasing systems.
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Summary

Active coherent beam combining of laser oscillators is an attractive way to achieve high output power in a diffraction limited beam. Here we describe an active beam combining system used to coherently combine 21 semiconductor laser elements with an 81% beam combining efficiency in an external cavity configuration compared with...

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Diffractive beam combining of a 2.5-kW fiber laser array

Published in:
ASSP 2012, Advanced Solid-State Photonics, 29 January - 1 February 2012.

Summary

Five 500-W fiber amplifiers were coherently combined with 79% efficiency using a diffractive optical element (DOE) combiner, generating a single beam whose M^2 = 1.1 beam quality exceeded that of the inputs.
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Summary

Five 500-W fiber amplifiers were coherently combined with 79% efficiency using a diffractive optical element (DOE) combiner, generating a single beam whose M^2 = 1.1 beam quality exceeded that of the inputs.

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Compact external-cavity semiconductor mode-locked laser with quantum-well-intermixed modulator and saturable absorber

Summary

We demonstrate a slab-coupled optical waveguide external-cavity mode-locked laser having unique bandedges for the amplifier, modulator and saturable absorber elements. An average output power of 50mW and timing jitter of 254fs is achieved at 1.5-GHz.
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Summary

We demonstrate a slab-coupled optical waveguide external-cavity mode-locked laser having unique bandedges for the amplifier, modulator and saturable absorber elements. An average output power of 50mW and timing jitter of 254fs is achieved at 1.5-GHz.

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Packaged, high-power, narrow-linewidth slab-coupled optical waveguide external cavity laser (SCOWECL)

Published in:
IEEE Photonics Technol. Lett., Vol. 23, No. 14, 15 July 2011.
Topic:

Summary

We report the demonstration of an InGaAlAs/InP quantum-well, high-power, low-noise packaged semiconductor external cavity laser (ECL) operating at 1550 nm. The laser comprises a double-pass, curved-channel slab-coupled optical waveguide amplifier (SCOWA) coupled to a narrow-bandwidth (2.5 GHz) fiber Bragg grating passive cavity using a lensedfiber. At a bias current of 4 A, the ECL produces 370 mW of fiber-coupled output power with a Voigt lineshape having Gaussian and Lorentzian linewidths of 35 kHz and 1 kHz, respectively, and relative intensity noise < -160 dB/Hz from 200 kHz to 10 GHz.
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Summary

We report the demonstration of an InGaAlAs/InP quantum-well, high-power, low-noise packaged semiconductor external cavity laser (ECL) operating at 1550 nm. The laser comprises a double-pass, curved-channel slab-coupled optical waveguide amplifier (SCOWA) coupled to a narrow-bandwidth (2.5 GHz) fiber Bragg grating passive cavity using a lensedfiber. At a bias current of...

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Cryogenic Yb3+ -doped materials for pulsed solid-state laser applications

Published in:
Opt. Mat. Expr., Vol. 1, No. 3, 1 July 2011, pp. 434-450.

Summary

We review recent progress in pulsed lasers using cryogenically-cooled Yb3+ -doped gain media, with an emphasis on high average power. Recent measurements of thermo-optic properties for various host material at both room and cryogenic temperature are presented, including themral conductivity, coefficient of thermal expansion and refractive index. Host materials reviewed include Y2O3, Lu2O3, Sc2O3, YLF, YSO, GSAG, and YVO4. We report on performance of several cryogenic Yb lasers operating at 5-kHz pulse repetition frequency (PRF) a Q-switched Yb:YAG laser is shwon to operate at 114-W average power, with 16-ns pulse duration. A chirped pulse amplifier achieves 115-W output using a composite Yb:YAG/Yb:GSAG amplifier, with pulses that compress to 1.6 ps. Finally, a high-average-power femtosecond laser based on Yb:YLF is discussed, with results for a 10-W regenerative amplifier at 10-kHZ PRF.
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Summary

We review recent progress in pulsed lasers using cryogenically-cooled Yb3+ -doped gain media, with an emphasis on high average power. Recent measurements of thermo-optic properties for various host material at both room and cryogenic temperature are presented, including themral conductivity, coefficient of thermal expansion and refractive index. Host materials reviewed...

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Advanced packaging of high-power slab-coupled optical waveguide laser and amplifier arrays for coherent beam combining

Summary

Individually addressable GaAs-based 9XX-nm Slab-Coupled Optical Waveguide (SCOW) laser and amplifier arrays have been demonstrated in a modular 2-D stacked architecture. Approximately 20 W of coherently-combined power was obtained from two optically stacked amplifier modules.
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Summary

Individually addressable GaAs-based 9XX-nm Slab-Coupled Optical Waveguide (SCOW) laser and amplifier arrays have been demonstrated in a modular 2-D stacked architecture. Approximately 20 W of coherently-combined power was obtained from two optically stacked amplifier modules.

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Beam combining of quantum cascade laser arrays

Published in:
Opt. Express, Vol. 17, No. 18, 31 August 2009, pp. 16216-16224.

Summary

Wavelength beam combining was used to co-propagate beams from 28 elements in an array of distributed-feedback quantum cascade lasers (DFB-QCLs). The beam-quality product of the array, defined as the product of near-field spot size and far-field divergence for the entire array, was improved by a factor of 21 by using wavelength beam combining. To demonstrate the applicability of wavelength beam combined DFB-QCL arrays for remote sensing, we obtained the absorption spectrum of isopropanol at a distance of 6 m from the laser array.
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Summary

Wavelength beam combining was used to co-propagate beams from 28 elements in an array of distributed-feedback quantum cascade lasers (DFB-QCLs). The beam-quality product of the array, defined as the product of near-field spot size and far-field divergence for the entire array, was improved by a factor of 21 by using...

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