Widely tunable quasi-phase-matched optical parametric amplification in infrared region using periodically poled lithium niobate

Widely tunable optical parametric amplification (OPA) in the IR region through quasi-phase-matching technology is demonstrated theoretically in periodically-poled lithium niobate (PPLN). For a 532nm pump wavelength and a broadband signal wavelength near 1300 nm, we can obtain the optimum grating period from phase-matching curves for different grating periods to achieve continuously tunable OPA by tuning the angle in a small range. Tunable OPA range of 200nm near 1300 mn can be obtained with a tuning incidence signal angle of 2.2 degrees.

Study of noncollinear quasi-phase matching optical parametric amplification with group-velocity matching based on periodically poled crystals

The properties of noncollinear optical parametric amplification (NOPA) based on quasi-phase matching of periodically poled crystals are investigated, under the condition that the group velocity matching (GVM) of the signal and idler pulses is satisfied. Our study focuses on the dependence of the gain spectrum upon the noncollinear angle, crystal temperature, and crystal angle with periodically poled KTiOPO4 (PPKTP), periodically poled LiNbO3 (PPLN), and periodically poled LiTaO3 (PPLT), and the NOPA gain properties of the three crystals are compared. Broad gain bandwidth exists above 85 nm at a signal wavelength of 800 nm with a 532 nm pump pulse, with proper noncollinear angle and grating period at a fixed temperature for GVM. Deviation from the group-velocity-matched noncollinear angle can be compensated by accurately tuning the crystal angle or temperature with a fixed grating period for phase matching. Moreover, there is a large capability of crystal angle tuning.

Investigation of near-collinear degenerated quasi-phase matching optical parametric amplification using PPKTP crystal

The gain properties of near-collinear degenerated phase-matched optical parametric amplification (OPA) using PPKTP crystal are investigated theoretically. The results indicate that the type-0 phase matching of PPKTP has larger accepted angle and better gain spectrum by tuning crystal temperature or rotating crystal angle.

Investigation of noncollinear QPM optical parametric amplification based on periodically poled KTP

The properties of noncollinear optical parametric amplification based on quasi-phase matching of periodically poled KTP are investigated theoretically. Our numerical simulation focuses on the gain spectrum of dependence upon noncollinear angle, crystal temperature and crystal angle. At the optimal noncollinear angle and grating period with fixed temperature, there exists a broadest gain bandwidth about 130 nm at signal wavelength of 800 nm. The deviation from optimal noncollinear angle can be compensated by accurately tuning the crystal angle or temperature with a fixed grating period for phase matching. (c) 2004 Elsevier B.V. All rights reserved.

Broad-bandwidth semi-noncollinear optical parametric amplification in periodically poled LiNbO3 based on tilted quasi-phase-matched gratings

On the basis of noncollinear optical parametric amplification in periodically poled lithium niobate (PPLN) which is realized by quasi-phase matching (QPM) technology, we consider the possibility of semi-noncollinear phase matching between collinear and noncollinear geometries by tilting a PPLN-crystal's parallel grating at a sure angle. Numerical simulation with proper parameters shows that we can achieve a broader optical parametric amplification (OPA) bandwidth than that of noncollinear geometry. About 121 nm at a signal wavelength of 800 and 70 nm at a signal wavelength of 1064 nm under optimal conditions are obtained when the crystal length is 9 mm.

Experimental and theoretical analysis of nondegenerate ultrabroadband chirped pulse optical parametric amplification

Experimental investigations of nondegenerate ultrabroadband chirped pulse optical parametric amplification have been carried out. The general mathematical expressions for evaluating parametric bandwidth, gain and gain bandwidth for arbitrary three-wave mixing parametric amplifiers are presented. In our experiments, a type-I noncollinear phase-matched optical parametric amplifier based on lithium triborate, which was pumped by a 5-ns second harmonic pulses from a Q-switched Nd:YAG operating at 10 Hz, seeded by a 14-fs Ti:sapphire laser at 800 nm, was presented. The 0.85 nJ energy of input chirped signal pulse with 57-FWHM has been amplified to 3.1 muJ at pump intensity 3 GW/cm(2), the corresponding parametric gain reached 3.6 x 10(3), the 53 nm-FWHM gain spectrum bandwidth of output signal has been obtained. The large gain and broad gain bandwidth, which have been confirmed experimentally, provide great potentials to amplify efficiently the broad bandwidth femtosecond light pulses to generate new extremes in power, intensity, and pulse duration using optical parametric chirped pulse amplifiers pumped by powerful nanosecond systems.

Investigation of spectral bandwidth of optical parametric amplification

The spectral bandwidth of three-wave-mixing optical parametric amplification has been investigated. A general mathematical model for evaluating the spectral bandwidth of optical parametric amplification is developed with parametric bandwidth and gain bandwidth via three-wave noncollinear interactions. The spectral bandwidth is determined by expanding the wave-vector mismatch in a Taylor series and retaining terms through second order. The model takes into account the effects of crystal length, noncollinear angle, group velocity, group-velocity dispersion and gain coefficient. The relation between parametric bandwidth and gain bandwidth is clearly defined. The model is applied to a BBO OPA, a LBO OPA and a CLBO OPA.

Stacking chirped pulse optical parametric amplification

Stacking chirped pulse optical parametric amplification based on a home-built Yb(3+)-doped mode-locked fiber laser and an all-fiber pulse stacker has been demonstrated. Energic 11 mJ shaped pulses with pulse duration of 2.3 ns and a net total gain of higher than 1.1 x 10(7) at fluctuation less than 2% rms are achieved by optical parametric amplification pumped by a Q-switched Nd:YAG frequency-doubled laser, which provides a simple and efficient amplification scheme for temporally shaped pulses by stacking chirped pulse. (C) 2009 Elsevier B.V. All rights reserved.

Regenerative amplifier with continuously variable pulse duration used in an optical parametric chirped-pulse amplification laser system for synchronous pumping

A Nd:glass regenerative amplifier has been set up to generate the pumping pulse with variable pulse width for an optical parametric chirped-pulse amplification (OPCPA) laser system. Each pulse of the pulse train from a cw self-mode-locking femtosecond Ti:sapphire oscillator is stretched to approximate to300 ps at 1062 nm to be split equally and injected into a nonlinear crystal and the Nd:glass regenerative amplifier, as the chirped signal pulse train and the seed pulse train of the pumping laser system, respectively. By adjusting the cavity length of the regenerative amplifier directly, the width of amplified pulse could be varied continuously from approximate to300 ps to approximate to3 ns. The chirped signal pulse for the OPCPA laser system and the seed pulse for the pumping laser system come from the same oscillator, so that the time jitter between the signal pulse and the pumping pulse in optical parametric amplification stages could be <10 ps. (C) 2003 Society of Photo-Optical Instrumentation Engineers.

Temporal synchronization in optical parametric chirped pulse amplification laser system

The effect of temporal synchronization between the chirped signal pulse and the pumping pulse in an optical parametric chirped pulse amplification laser system is researched theoretically and experimentally. The results show that the gain of optical parametric amplification is sensitive to the temporal synchronization. Therefore, accurate temporal synchronization between the chirped signal pulse and the pumping pulse is essential to obtain high optical parametric amplification gain and stable output from an optical parametric chirped pulse amplification laser. Based on our 16.7-TW/120-fs optical parametric chirped pulse amplification laser system with similar to1-ns pumping pulse duration and <10-ps time jitter between the signal and pumping pulse, the effect of the temporal synchronization on optical parametric chirped pulse amplification is demonstrated. The experimental results agree with the calculation. (C) 2004 Society of Photo-Optical Instrumentation Engineers.

Dispersion analysis and compensation of collinear optical parametric chirped pulse amplification systems

In an optical parametric chirped pulse amplification (OPCPA) laser system, residual phase dispersion should be compensated as much as possible to shorten the amplified pulses and improve the pulse contrast ratio. Expressions of orders of the induced phases in collinear optical parametric amplification (OPA) processes are presented at the central signal wavelength to depict a clear physics picture and to simplify the design of phase compensation. As examples, we simulate two OPCPA systems to compensate for the phases up to the partial fourth-order terms, and obtain flat phase spectra of 200-nm bandwidth at 1064 nm and 90-nm at 800 nm.

Optimization of optical parametric chirped pulse amplification with different pump wavelengths

Optical parametric chirped pulse amplification with different pump wavelengths was investigated using LBO crystal, at signal central wavelength of 800 nm. According to our theoretical simulation, when pump wavelength is 492.5 nm, there is a maximal gain bandwidth of 190 nm. centered at 805 nm in optimal noncollinear angle using LBO. Presently, pump wavelength of 492.5 nm can be obtained from second harmonic generation of a Yb:Sr-5(PO4)(3)F laser. The broad gain bandwidth can completely support similar to 6 fs with a spectral centre of seed pulse at 800 nm. The deviation from optimal noncollinear angle can be compensated by accurately tuning crystal angle for phase matching. The gain spectrum with pump wavelength of 492.5 nm is much better than those with pump wavelengths of 400, 526.5 and 532 nm, at signal centre of 800 nm. (c) 2005 Elsevier B.V. All rights reserved.

Compact and efficient triple-pass optical parametric chirped pulse amplification

Compact and efficient triple-pass optical parametric chirped pulse amplification in a single crystal has been demonstrated. The signal was triple-pass amplified in a single nonlinear crystal by a nanosecond pump pulse. The first-pass optical parametric amplification is completely phase matched in the plane of the maximum effective nonlinearity, and the other two passes work symmetrically near to the first-pass optical parametric amplification plane. This architecture efficiently increases the overall gain, overcomes the optical parametric fluorescence, and clearly simplifies the amplification scheme.

Design of a highly stable, high-conversion-efficiency pumping source for optical parametric amplifier by extending efficient crystal length

The objective of this study is to improve the stability of pumping source of optical parametric amplifier. Analysis by simulation leads to the conclusion that the stability of the second harmonic can be improved by using properly the intensity of fundamental light and corresponding length of the crystal. By the method of the noncollinear two-pass second harmonic or the tandem second harmonic, the efficient crystal length is extended to a proper value, and the stability of the second harmonic output has been improved two times more than that for the fundamental light, and the conversion-efficiency is about 70% in experiment. When the variation of the fundamental light is about 10%, the variation of the second harmonic intensity has been controlled within 5%. (c) 2006 Elsevier Ltd. All rights reserved.