Femtosecond noncollinear and collinear parametric generation and amplification in BBO crystal

Krylov, V. N.; Gallus, J.; Wild, Urs P.; Kalintsev, A. G.; Rebane, Aleksander

doi:10.1007/s003400050026

Cited by 23 publications

(11 citation statements)

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“…18,19 In the latter case, continuum seed pulses are generated by focusing the 800 nm beam in a 2 mm sapphire plate and amplified in a 3 mm BBO ͑31°, Type I phasematching͒ pumped by the 400 nm pumping beam. The wavelength can be tuned from 480 nm to 650 nm by changing the BBO crystal angle and the angle between the seed and the pump beams.…”

Section: Methodsmentioning

confidence: 99%

The role of long-lived dark states in the photoluminescence dynamics of phenylene vinylene conjugated polymers

Lim

Bjorklund

Gaab

et al. 2002

The Journal of Chemical Physics

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Femtosecond studies of exciton dynamics in a novel main chain chiral conjugated poly(arylenevinylene)The role of intermediate nonluminescent states in the relaxation of singlet excitons in the conjugated polymer poly͑phenylene vinylene͒ ͑PPV͒ and its soluble derivative poly͓(2-methoxy-5-hexyloxy-p-phenylene) vinylene͔ ͑MH-PPV͒ is investigated. Time-resolved luminescence and absorption measurements provide evidence for a long-lived, weakly emissive species in PPV at 17 K, in addition to the luminescent singlet state. Ground state recovery times at this temperature provide evidence that up to 40% of the initially excited chromophores end up in a state that does not relax back to the ground state on the 5 ns time scale of the experiment. As the temperature is raised from 17 K to 290 K, the redshifted emission disappears, the fluorescence decay becomes more rapid, and the magnitude of the long-time bleach decreases. These results can be understood in terms of a three-level model where the initially excited singlet state decays nonradiatively via two separate channels: thermally-activated direct relaxation to the ground state, and nanosecond relaxation into a third, long-lived dark state. As the temperature increases, the thermally-activated process increases at the expense of both the fluorescence and the intermediate dark state population. Using this model, a temperature-independent dark state formation time of 1.8 ns was found for PPV, and 1.1 ns for MH-PPV. Our data and modeling provide no evidence for a subpicosecond relaxation channel in the decay of the luminescent excitons in these phenylene vinylene polymers.

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Section: Methodsmentioning

confidence: 99%

The role of long-lived dark states in the photoluminescence dynamics of phenylene vinylene conjugated polymers

Lim

Bjorklund

Gaab

et al. 2002

The Journal of Chemical Physics

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“…The technique has been widely applied to gas and particle phase absorption measurements. Arnott et al (1999) and Nägele and Sigrist (2000) provide comprehensive descriptions of the PAS technique which the reader is referred to for further details.…”

Section: Instrument Designmentioning

confidence: 99%

Aircraft Instrument for Comprehensive Characterization of Aerosol Optical Properties, Part 2: Black and Brown Carbon Absorption and Absorption Enhancement Measured with Photo Acoustic Spectroscopy

Lack

Richardson

Law

et al. 2012

Aerosol Science and Technology

145

190

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This paper describes the design and performance of a photoacoustic aerosol absorption spectrometer (PAS) built for operation on a research aircraft platform. The PAS instrument is capable of measuring dry absorption at 659 nm, 532 nm, and 404 nm, and absorption enhancement due to coatings at 532 nm and 404 nm. The measurement accuracy for all channels is < = 10% and inflight 1 Hz sensitivities lie within the range of 0.5-1.5 Mm −1 . PAS measurements of calibrated absorbing aerosol samples are shown to be consistent with measurements made by a previous generation single channel photo-acoustic instrument. Aircraft data collected during a recent field campaign in California are used to demonstrate the capabilities of the PAS. In combination with an aircraft cavity ring down aerosol extinction spectrometer described in a companion paper, the new PAS instrument provides a sensitive airborne in-situ characterization of aerosol optics.

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“…As is well-known for all nonlinear-optical processes, achieving phase-matching across the entire pulse bandwidth limits the crystal thickness and hence the efficiency 15 . The second limiting factor in an OPA imaging system is OPG 16,17 , the generation of parametric super-fluorescence from quantum mechanical processes due to the use of an input pump of high intensity. The background generated by OPG degrades the amplified image and competes for available pump-beam energy.…”

Section: Optimizing Gain During Opa Imagingmentioning

confidence: 99%

Optical-parametric-amplification imaging of complex objects

Vaughan

Trebino

2011

Nonlinear Frequency Generation and Conversion: Materials, Devices, and Applications X

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We used ultrafast Fourier-plane optical-parametric-amplification (OPA) imaging to simultaneously image, wavelength-shift, and amplify complex two-dimensional objects with spatial features from 1.1 to 11.3 line-pairs/millimeter, corresponding to a two-dimensional space-bandwidth product (SBP) of 13,790. This represents an increase in image complexity over previous analogous OPA imaging systems by almost three orders of magnitude. In wavelength-shifting the image from 930nm to an idler wavelength of 700nm, we observed image amplification by up to two orders of magnitude. OPTICAL-PARAMETRIC-AMPLIFICATION IMAGINGThe ultrahigh intensities available from ultrafast-laser technology allow access to a wide range of high-intensity phenomena and techniques. Whereas earlier laser systems required tightly focused beam spots in order to achieve sufficient intensities, recent advances in Ti:Sapphire regenerative amplifiers ("regens") allow high-intensity interactions of unfocused beams with relatively large diameters. Vastly improved stability in such systems also makes practical previously impractical highly nonlinear processes.Optical parametric amplification (OPA) 1 , in particular, which experiences gain that is an exponential of the pump-beam amplitude, benefits greatly from these technological advances. OPA has long been used to nonlinear-optically amplify weak input signals 2 , as well as to wavelength-convert them, usually from the infrared into the visible 3 . Unfortunately, due to its highly nonlinear nature, OPA is very sensitive to and severely limited by shot-to-shot jitter of the laser. Pulses that are too weak can yield no signal, and pulses that are too intense can yield undesirable background in the form of optical-parametric generation (OPG) or, worse, can damage the crystal. Such issues significantly complicate applications of OPA, and, as a result, OPA, perhaps more than any other optical process, benefits from the high intensity and, especially, the vastly improved shot-to-shot jitter of these laser systems.Indeed, the use of OPA for imaging applications (see Fig. 1) should benefit greatly. OPA imaging involves imaging an object (or target) with amplification and perhaps also simultaneous wavelength conversion, spatial-frequency filtering, time-gating and phase conjugation. An imaging system images or focuses the target onto a nonlinear medium, where an OPA pump beam amplifies (and potentially wavelength shifts and time-gates) it, and an additional imaging or focusing system transfers the image from the OPA medium to a camera (or free space propagation onto the camera results in phase-conjugation).The first demonstration of OPA imaging occurred in 1968, when Midwinter amplified and frequency-shifted an IR image to the visible 4, 5 . Since then, both monochromatic 6 and polychromatic 7 images have been amplified. When OPA is performed to amplify or frequency-shift an image, the interaction takes place between the signal and pump beams in the nonlinear medium, but different interaction planes can be used, dep...

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Femtosecond noncollinear and collinear parametric generation and amplification in BBO crystal

Cited by 23 publications

References 1 publication

The role of long-lived dark states in the photoluminescence dynamics of phenylene vinylene conjugated polymers

The role of long-lived dark states in the photoluminescence dynamics of phenylene vinylene conjugated polymers

Aircraft Instrument for Comprehensive Characterization of Aerosol Optical Properties, Part 2: Black and Brown Carbon Absorption and Absorption Enhancement Measured with Photo Acoustic Spectroscopy

Optical-parametric-amplification imaging of complex objects

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