Chirped Pulse Amplification System Research Articles

Chirped-pulse amplification system based on chirp reversal and near-field spatial reversal with common tiled grating pair as stretcher and compressor

Chirped-pulse amplification system based on chirp reversal in optical parametric chirped-pulse amplification is proposed and experimentally demonstrated. The operation of this system can be described as negative stretching-temporal chirp reversal-energy amplification-negative compression, in which the pulse is stretched and compressed with the same gratings. Stand-alone stretcher adopting lenses or concave mirrors with large aperture can be omitted. Simulations showed that this work mode can also increase the cut-off band-pass of the whole system and increase the output energy by 15-17%. In addition, the stability of a tiled-grating compressor can be improved with this work mode.

High-energy Nd : YAG-amplification system for OPCPA pumping**Reported at the conference ‘Laser Optics 2010’, St. Petersburg, Russia.

We present a high-energy picosecond Nd:YAG-amplification system seeded with pulses of a femtosecond Yb:KGW oscillator. The Nd : YAG amplifier is intended to pump an optical parametric chirped-pulse amplification (OPCPA) system. Generation of high contrast pulses with energy of 600 mJ and pulse duration of 100 ps is demonstrated.

Design Considerations for Dispersion Control with a Compact Bonded Grism Stretcher for Broadband Pulse Amplification

We report on the design of a compact grism-pair stretcher for a near-infrared noncollinear optical parametric chirped-pulse amplification (OPCPA) system. The grisms are produced by bonding a grating to a prism using a resin. The stretcher is capable of controlling a bandwidth of over 300 nm, which is suitable for parametric amplification of few-cycle pulses. After amplification, pulses can be compressed by the dispersion of optical glass, and the residual group-delay can be compensated with an acousto-optic programmable dispersive filter (AOPDF).

Spatial degradation of pulse contrast in the focal plane for pulsed laser beams from chirped-pulse amplification system

A two-dimension model is presented to analyze the spatial dependence of pulse contrast in the focal plane. The parameters of the SHENGUANG (SG) II laser system are demonstrated as examples. Comparing with the degradation in the beam centroid, the pulse contrast degrades more seriously in the transverse. This spatial degradation of pulse contrast can be improved, such as by controlling the spatial spectrum clipping.

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

We present a high-repetition-frequency, diode-pumped, and chirped-pulse amplification system operating at 106 W average output power 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.

Improvement of contrast ratio in saturated OPCPA system by using pump pulse shaping and time delay control

We theoretically investigated the temporal profile of a background pedestal in a single-stage optical parametric chirped pulse amplification (OPCPA) system, and showed that the amplified spontaneous emission (ASE) prepulse in the saturation regime degrades the contrast ratio. To improve the contrast ratio in a saturated OPCPA system, a method using pump pulse shaping and the time delay control between pump and seed pulses was utilized. Through numerical simulations, the effect of the rising time and the time delay of a pump pulse on the background pedestal was subsequently investigated in terms of the contrast ratio. From the simulation results, it was determined that an optimal rising time and the time delay of the pump pulse are critical for obtaining a high-contrast broadband laser pulse from a saturated OPCPA system.

Theoretical analysis of ASE contrast improvement with a rapid scanning F–P interferometer in a CPA system

The use of a rapid scanning Fabry–Pérot (F–P) interferometer as a scanning spectral filter to improve the amplified spontaneous emission (ASE) contrast in a chirped pulse amplification (CPA) laser is proposed and analyzed numerically. The numerical simulation results show that the ASE contrast can be improved by the rapid scanning Fabry–Pérot interferometer by about two orders, and the transmission efficiency of the chirped pulse can exceed 80% with the synchronizing time jitter ranging from − 5 to 5 ps. Use of the cascaded rapid scanning F–P interferometer method to improve the ASE contrast is investigated too, which can improve the ASE contrast further.

Measurement of high time-bandwidth pulses on a chip with SPIDER

We develop a method capable of characterizing both the amplitude and phase of ultrafast optical pulses with the aid of a synchronized incoherently-related clock pulse based on a novel variation of SPIDER. It exploits degenerate four-wave-mixing and its design is amenable for full ?on chip? signal characterization. By implementing our method in a CMOS compatible waveguide, we measure pulses with 1THz, and up to 100ps pulsewidths. Our novel reconstruction algorithm that we call Fresnel-Limited Extraction Procedure (FLEA), yields a time-bandwidth product (TBP)>100. Full Text: PDF References R. Trebino, "Frequency Resolved Optical Gating: the Measurement of Ultrashort Optical Pulses", (Kluwer Academic, 2002) [CrossRef] I. A. Walmsley and C. Dorrer, "Characterization of ultrashort electromagnetic pulses", Adv. Opt. Photon. 1, 308-437 (2009) [CrossRef] Nature Photonics Workshop on the future of optical communication,Tokyo, Oct. 2007. M. A. Foster et al.,"Silicon-chip-based ultrafast optical oscilloscope", Nature 456, 81-84 (2008) [CrossRef] E. K. Tien, X. Z. Sang, F. Qing, Q. Song, and O. Boyraz., "Ultrafast pulse characterization using cross phase modulation in silicon", Appl. Phys. Lett. 95, 051101 (2009) [CrossRef] A. Pasquazi et al.,"Sub-picosecond phase-sensitive optical pulse characterization on a chip", [CrossRef] C. Iaconis and I.A. Walmsley,"Spectral phase interferometry for direct electric-field reconstruction of ultrashort optical pulses", Opt. Lett., 23, 792-794 (1998) [CrossRef] L. Gallmann et al.,"Characterization of sub-6-fs optical pulses with spectral phase interferometry for direct electric-field reconstruction", Opt. Lett., 24, 1314-1316 (1999) [CrossRef] C. Dorrer et al.,"Single-shot real-time characterization of chirped-pulse amplification systems by spectral phase interferometry for direct electric-field reconstruction", Opt. Lett., 24, 1644-1646 (1999) [CrossRef] D. Keusters et al.,"Relative-phase ambiguities in measurements of ultrashort pulses with well-separated multiple frequency components", J. Opt. Soc. Am. B, 20, 2226-2237 (2003) [CrossRef] M. Hirasawa et al.,"Sensitivity improvement of spectral phase interferometry for direct electric-field reconstruction for the characterization of low-intensity femtosecond pulses", Appl. Phys. B, 74, S225-S229 (2002) [CrossRef] J. Wemans, G. Figueira, N. Lopes and L. Cardoso,"Self-referencing spectral phase interferometry for direct electric-field reconstruction with chirped pulses", Opt. Lett., 31, 2217-2219 (2006)Self-referencing spectral phase interferometry for direct electric-field reconstruction with chirped pulses [CrossRef] M. Peccianti et al.,"Subpicosecond optical pulse compression via an integrated nonlinear chirper", Opt. Express, 18, 7625-7633 (2010) [CrossRef] A. Pasquazi et al.,"All-optical wavelength conversion in an integrated ring resonator", Opt. Express 18, 3858-3863 (2010) [CrossRef]

Numeral analysis of spectral shaping based on superstructure fiber Bragg grating in high-power Nd:glass chirped pulse amplification system

Using the genetic algorithm, we design a superstructure fiber Bragg grating (SSFBG) to pre-compensate gain narrowing and gain saturation effects in a high-power Nd:glass chirped pulse amplification system. An inverse engineering operation of chirped pulse amplification processing is used to calculate the target spectrum of the seed pulse and then the response function of the SSFBG can be obtained. Some numerical simulations are given to realize a 20μJ, 15nm ultrashort seed pulse to the hundreds Joules, 8nm optimal fourth order super-Gaussian chirped pulses in a high power Nd:glass amplification system. The results show that the gain narrowing and gain saturation effects will be reduced largely when a SSFBG, which has a proper refractive index modulation distribution, chirp coefficient and length, is used. It is believed that this proposed method will provide a theoretical direction for the future experiment. Moreover, it will also be useful and flexible for the spectral transform in other chirped pulse application areas.

Demonstration of a double chirped-pulse-amplification front-end system to improve the temporal contrast at a sub-petawatt laser

The temporal contrast is an important factor affecting the application of ultra-intense and ultra-short lasers. In this paper, we develop a double chirped-pulse-amplification (CPA) front-end system with an intermediate nonlinear temporal pulse filter to improve the temporal contrast at a sub-petawatt Ti:sapphire laser facility, i.e. the super intense laser for experiment on the extremes (SILEX-I). The temporal pulse filter employs cross-polarized wave (XPW) generation to suppress the amplified spontaneous emission (ASE). The design output energy is 320 mJ for the front-end system. The experimental results show that the output energy of the double CPA system is 360 mJ. The ASE pedestal is suppressed significantly and the temporal contrast is improved by around three orders of magnitude.

Experimental and theoretical investigation of timing jitter inside a stretcher-compressor setup

In an optically synchronized short-pulse optical-parametric chirped-pulse amplification (OPCPA) system, we observe a few-100 fs-scale timing jitter. With an active timing stabilization system slow fluctuations are removed and the timing jitter can be reduced to 100 fs standard deviation (Std). As the main source for the timing fluctuations we could identify air turbulence in the stretcher-compressor setup inside the chirped pulse amplification (CPA) pump chain. This observation is supported by theoretical investigation of group delay changes for angular deviations occurring between the parallel gratings of a compressor or stretcher, as they can be introduced by air turbulence.

Signal-to-noise ratio of ultrashort pulses enhanced by a fiber Sagnac loop

A method to enhance the signal-to-noise ratio of ultrashort pulses is presented with picosecond pulses as an example. Numerical simulation and analysis show that the signal-to-noise ratio can be improved by four orders of magnitude using a fiber Sagnac loop with two different fibers. It is also found that there is an optimal length of the fiber for improving the signal-to-noise ratio. This is a useful method for improving the signal-to-noise ratio of the seed light in the chirped pulse amplification (CPA) or optical parametric chirped pulse amplification (OPCPA) systems.

Chirped pulse amplification of femtosecond pulse sequences in a Ti: sapphire laser

An amplified femtosecond pulse sequence is generated in a multi-TW Ti: sapphire chirped pulse amplification system (JG-II facility). The pulse interval of the pulse sequence is 14.8 ns, corresponding to a frequency of 67.5 MHz. The compressed pulse sequence can reach 122 mJ in 19 independent pulses with a pulse width of about 60 fs. The energy of the pulses declines from 20 mJ to 0.5 mJ, corresponding to a peak power from 1011 W to 1010 W. The pulse sequence has important applications in lengthening the lifetime of the laser produced plasma channel in air and in microfabrication.

Direct Generation of 4.6-nJ 78.9-fs Dissipative Solitons in an All-Fiber Net-Normal-Dispersion Er-Doped Laser

We have demonstrated the direct generation of 4.6-nJ 78.9-fs ultrashort pulses with 58 kW peak power in an all-fiber net-normal-dispersion oscillator. Such high peak power is a record in an all-fiber oscillator and is comparable to chirped-pulse amplification systems. The corresponding spectrum has steep spectral edges, which is the typical shape of dissipative solitons (DS). Also, we find that the spectral width is tunable from 40 to 58 nm by adjusting polarization controllers, and the pulse duration can be tuned from 1.7 ps to 120 fs through increasing the pump power, which is attractive to applications. Besides, we demonstrate experimentally the relationship between spectral width and the pump power of DS laser for the first time.

1 MHz repetition rate hollow fiber pulse compression to sub-100-fs duration at 100 W average power

We report on nonlinear pulse compression at very high average power. A high-power fiber chirped pulse amplification system based on a novel large pitch photonic crystal fiber delivers 700 fs pulses with 200 μJ pulse energy at a 1 MHz repetition rate, resulting in 200 W of average power. Subsequent spectral broadening in a xenon-filled hollow-core fiber and pulse compression with chirped mirrors is employed for pulse shortening and peak power enhancement. For the first time, to our knowledge, more than 100 W of average power are transmitted through a noble-gas-filled hollow fiber. After pulse compression of 81 fs, 93 μJ pulses are obtained at a 1 MHz repetition rate.

Carrier-envelope phase stabilization of a terawatt level chirped pulse amplifier for generation of intense isolated attosecond pulses

We demonstrate the first carrier-envelope phase (CEP)-stabilized chirped pulse amplification system with pulse peak-powers in the terawatt regime. The system, which eventually is intended to be used in the generation of isolated attosecond pulses, consists of two consecutive multipass amplification stages. The first amplification stage is a commercial CEP-stable kHz system including a single 13-pass amplifier reaching a pulse energy of 2.3 mJ. Pulses are picked after the first stage at a repetition rate of 50 Hz and are further amplified in a 5-pass power-amplifier to pulse energies that reach up to 80 mJ before compression. After compression the pulse energy is 35mJ at a pulse duration of 32 fs, signifying a peak power of 1.1 terawatt. Peak-powers exceeding 1.5 TW should easily be achievable by improving the efficiency of the grating compressor. The CEP-stability of the terawatt system is demonstrated by single shot measurements of the residual CEP jitter at the full repetition rate and show an excellent root-mean-square value of 315 mrad.

Sub-200 fs microjoule pulses from a monolithic linear fiber CPA system

An all-fiber-integrated linear chirped-pulse amplifier system generating microjoule pulse energies is reported. It is seeded by an all-fiber dissipative-soliton laser and incorporates a newly developed fiber stretcher, whose dispersive properties match that of the grating compressor. Pulse durations of 189 fs with energies of 2.2 μJ were achieved after compression. The average power was 9.8 W at the repetition rate of 4.5 MHz.

Sub-250-mrad, passively carrier–envelope-phase-stable mid-infrared OPCPA source at high repetition rate

An all-optical and passively carrier-to-envelope-phase-stabilized (CEP-stabilized) optical parametric chirped pulse amplification (OPCPA) system is demonstrated with sub-250-mrad CEP stability over 11 min and better than 100 mrad over 11 s. This is achieved without any electronic CEP stabilization loop for 160 kHz pulse repetition rate in the few cycle regime.

Ultrabroadband TW-class Ti:sapphire laser system with adjustable central wavelength, bandwidth and multi-color operation

We demonstrate a versatile tunable and highly stable ultrabroadband Ti:sapphire chirped pulse amplification system with a compressed pulse energy of 20 mJ at 100 Hz repetition rate. High power Ti:Sa systems in principle do not offer wavelength tunability due to gain narrowing. Here we demonstrate transform limited pulse generation from 15 fs to 94 fs with tunable central wavelength (λc from 755 nm to 845 nm) and bandwidth (130 nm<Δλ<16 nm) as well as multi-color, time synchronized, sub-100 fs pulses with user defined central wavelength separation. The unique wavelength tunability capabilities have been expanded into the UV and deep-UV by second and third harmonic generation with excellent energy stability. Enhanced energy stability is achieved by multiplexing six ultrastable diode-based solid state pump lasers.

Microjoule level femtosecond optical pulses with double-cladding fiber-based nonlinear chirped-pulse amplification

An all-fiber high-energy nonlinear chirped-pulse amplification system with two-stage double-cladding fiber amplifiers is presented in this paper. It generates pulses with the energy up to 10 μJ at 20 kHz repetition rate and total accumulated nonlinear phase shift as large as 12.8π. The pulses can be compressed to 137 fs with the compensation of mismatched third-order dispersion by self-phase modulation in the fiber amplifiers.