Showing papers by "Fredrik Laurell published in 2012"
TL;DR: In this article, the authors give a short description of design principles of one-dimensional and two-dimensional quasi-phase matched structures and emphasize the increased functionality afforded by such structures and also overview the nonlinear media where engineering of nonlinear interactions has been demonstrated with the primary focus on ferroelectric and semiconductor nonlinear crystals.
39 citations
TL;DR: Femto-second laser writing was used to fabricate waveguides in a z-cut KTP sample with losses below 0.8 dB/cm, and they were used for efficient, broad bandwidth, Type II birefringent second harmonic generation to the green.
Abstract: Femto-second laser writing was used to fabricate waveguides in a z-cut KTP sample with losses below 0.8 dB/cm. They were used for efficient, broad bandwidth, Type II birefringent second harmonic generation to the green. The temperature and wavelength bandwidth were, 28⁰C∙cm and 0.85 nm∙cm, respectively.
25 citations
TL;DR: This work demonstrates an actively mode-locked fiber laser operating in soliton regime and employing an all-fiber electro-optic modulator using nonlinear polarization rotation for femtosecond pulse generation.
Abstract: This work demonstrates an actively mode-locked fiber laser operating in soliton regime and employing an all-fiber electro-optic modulator. Nonlinear polarization rotation is utilized for femtosecond pulse generation. Stable operation of the all-fiber ring laser is readily achieved at a fundamental repetition rate of 2.6 MHz and produces 460 fs pulses with a spectral bandwidth of 5.3 nm.
19 citations
TL;DR: In this article, a 9mm long periodically poled KTiOPO4 (PPKTP) crystal was employed in an optical parametric oscillator to generate sub-nanosecond idler pulses around 2.8μm.
Abstract: We employed a 9-mm long periodically poled KTiOPO4 (PPKTP) crystal in an optical parametric oscillator (OPO) to generate sub-nanosecond idler pulses around 2.8 μm. With a 1-cm long OPO cavity in a singly resonant configuration and double pass pumping by 1-ns pulses at 1,064 nm, the maximum idler energy reached 110 μJ at 1 kHz. Pumping with 500 ps pulses at 1–10 kHz, resulted in an idler energy of ~50 μJ and the shortest pulse duration of ~250 ps, ever reported for an OPO. The corresponding quantum conversion efficiencies were 32.5 and 34.9 %, respectively.
19 citations
TL;DR: It is demonstrated that parametric collateral processes may deplete or enhance spectral portions of the OPG output, depending on pump pulse duration.
Abstract: We theoretically and experimentally investigate multistep parametric processes in broadband optical parametric generators (OPGs) based on periodically poled 1 mol. % MgO-doped stoichiometric LiTaO3. We demonstrate that parametric collateral processes may deplete or enhance spectral portions of the OPG output, depending on pump pulse duration.
13 citations
TL;DR: In this paper, a 9mm long periodically poled KTiOPO4 (PPKTP) crystal was employed in an optical parametric oscillator (OPO) to generate sub-nanosecond idler pulses around 2.8 lm.
Abstract: We employed a 9-mm long periodically poled KTiOPO4 (PPKTP) crystal in an optical parametric oscillator (OPO) to generate sub-nanosecond idler pulses around 2.8 lm. With a 1-cm long OPO cavity in a singly resonant configuration and double pass pumping by 1-ns pulses at 1,064 nm, the maximum idler energy reached 110 l Ja t 1 kHz. Pumping with 500 ps pulses at 1-10 kHz, resulted in an idler energy of*50 lJ and the shortest pulse duration of*250 ps, ever reported for an OPO. The corresponding quantum con- version efficiencies were 32.5 and 34.9 %, respectively.
12 citations
01 Jan 2012
TL;DR: Two 78-cm long electrooptic fibers with nonlinear coefficient χ((2)) ~0.26 pm/V are used in a Sagnac loop for pulse selection at up to 1 MHz repetition rate and the arrangement is entirely based on silica fiber.
Abstract: Two 78-cm long electrooptic fibers with nonlinear coefficient χ((2)) ~0.26 pm/V are used in a Sagnac loop for pulse selection at up to 1 MHz repetition rate. Laser pulses of 1.5 µm wavelength arriving at every 140 ns are selected with an extinction ratio as high as -30 dB. The arrangement is entirely based on silica fiber.
11 citations
06 May 2012
TL;DR: In this article, a short-cavity, singly-resonant OPO based on PPKTP, pumped by a 1-10 kHz, 500 ps, 1064 nm laser source, was used to obtain idler pulses at 2.8 μm with energy of ∼ 50 μJ and ∼ 250 ps pulse duration.
Abstract: Idler pulses at 2.8 μm with energy of ∼ 50 μJ and ∼ 250 ps pulse duration are obtained from a short-cavity, singly-resonant OPO based on PPKTP, pumped by a 1–10 kHz, 500 ps, 1064 nm laser source.
5 citations
TL;DR: In this article, a Nd:YVO4 laser was locked with a chirped volume Bragg grating to achieve single-longitudinal-mode output, which could be frequency doubled in PPKTP with a conversion efficiency exceeding 50%.
Abstract: A Nd:YVO4 laser was locked with a chirped volume Bragg grating to achieve single-longitudinal-mode output. Tuning was performed from 1,063 to 1,065 nm by translating the grating and a maximum output power of 4 W was obtained. With a Cr4+:YAG saturable absorber, Q-switched pulses with 4 ns and a pulse energy of 5.7 μJ were achieved which could be frequency doubled in PPKTP with a conversion efficiency exceeding 50 %.
5 citations
TL;DR: In this article, an epitaxial growth process using seeds made of thin plates domain engineered by electric field poling was proposed to increase the size of periodically domain-structured ferroelectric crystals with a controlled and regular grating period.
4 citations
06 May 2012
TL;DR: In this article, a system based on laser-induced fluorescence combined with microstructured fiber for micrometer-size sample detection and collection is presented, which introduces the possibility for real-time monitoring in in-vivo measurements.
Abstract: A technology based on laser-induced fluorescence combined with microstructured fiber for micrometer-size sample detection and collection is presented. The fiber-based system introduces the possibility for real-time monitoring in in-vivo measurements.
01 Jan 2012
TL;DR: Femto-second laser writing was used to fabricate waveguides in KTP with losses below 0.8 dB/cm as discussed by the authors, which were used for efficient broad bandwidth, Type II frequency doubling of cwTi-sapphire laser radiati...
Abstract: Femto-second laser writing was used to fabricatewaveguides in KTP with losses below 0.8 dB/cm. They were usedfor efficient broad bandwidth, Type II frequency doubling of cwTi-sapphire laser radiati ...
06 May 2012
TL;DR: In this paper, the phase reversal of the polaritons generated in Cherenkov phase-matched direction was investigated. And the dependence of stimulated Raman scattering threshold on crystal rotation angle and poling period was shown.
Abstract: Periodic poling in KTP leads to periodic phase reversal of the polaritons generated in Cherenkov phase-matched direction. This is responsible for the dependence of stimulated Raman scattering threshold on crystal rotation angle and poling period.
02 Jul 2012
TL;DR: In this article, the authors discuss the unique coherence properties of counter-propagating parametric interaction in such structures and propose a method to construct a ferroelectric nonlinear materials with sub-micrometer periodicity domains.
Abstract: Progress in structuring ferroelectric nonlinear materials with sub-micrometer periodicity domains for counter-propagating nonlinear interactions is overviewed. As an example of device realisation, the unique coherence properties of counter-propagating parametric interaction in such structures are dicussed.
06 May 2012
TL;DR: In this paper, the spectral and angular degrees of freedom of multi-resonant optical parametric generation in hexagonally poled LiTaO 3 were investigated experimentally.
Abstract: We investigate experimentally the spectral and angular degrees of freedom of multi-resonant optical parametric generation in hexagonally poled LiTaO 3 and demonstrate access to twin-beam output for either signal or idler waves by pump angle tuning.
29 Jan 2012
TL;DR: In this paper, the authors investigate theoretically and experimentally multistep processes in broadband optical parametric generation (OPG) and demonstrate the possibility to control fine features in the gain spectra via the OPG pump.
Abstract: We investigate theoretically and experimentally multistep processes in broadband optical parametric generation (OPG) and demonstrate the possibility to control fine features in the gain spectra via the OPG pump
06 May 2012
TL;DR: In this article, a self-assembled bulk domain gratings of sub-μm periodicity in Rb-doped KTiOPO 4 crystals were constructed and used to demonstrate QPM backwards propagating non-collinear second harmonic generation.
Abstract: We present the fabrication of self-assembled bulk domain gratings of sub-μm periodicity in Rb-doped KTiOPO 4 crystals. The structures are used to demonstrate QPM backwards propagating non-collinear second harmonic generation.