Dual-chirped Optical Parametric Amplification Research Articles

Non-collinear broadband phase-matching for dual-chirped optical parametric amplification

Non-collinear broadband phase-matching for dual-chirped optical parametric amplification

Octave-spanning supercontinuum coherent soft x-ray for producing a single-cycle soft x-ray pulse.

This study demonstrates the potential to generate a soft x-ray single-cycle attosecond pulse using a single-cycle mid-infrared pulse from advanced dual-chirped optical parametric amplification (DC-OPA). A super continuum high harmonic (HH) spectrum was generated in argon (80-160 eV) and neon (150-270 eV). The experimental spectra reasonably agree with those calculated by the strong-field approximation model and Maxwell's equations. In addition, simulation results indicate that the dispersion of HHs in argon can be compensated using a 207-nm Zr filter to obtain 40 as (Fourier transform limited (FTL)) pulses (1.1 cycles at 118 eV). For neon, a 278-nm Sn filter can compensate for the dispersion of HH and create 23 as FTL pulses (1.1 cycles at 206 eV). This soft x-ray single-cycle attosecond pulse is expected to be highly valuable for ultrafast science and applications in quantum information science.

Dual-chirped optical parametric amplification of high-energy single-cycle laser pulses

We demonstrate how a scheme called advanced dual-chirped optical parametric amplification (DC-OPA) that employs two kinds of nonlinear crystal (BiB3O6 and MgO-doped lithium niobate) can generate high-energy, single-cycle mid-infrared laser pulses. In experiments, the advanced DC-OPA scheme achieved carrier-to-envelope phase-stable mid-infrared laser pulses with a bandwidth of over one octave (1.4–3.1 µm) and an output pulse energy of 53 mJ. The pulse duration was compressed to 8.58 fs, which corresponds to 1.05 cycles with a central wavelength of 2.44 µm and a peak power of 6 TW. To our knowledge, the obtained values for the pulse energy and peak power are the highest achieved for optical parametric amplification of single-cycle mid-infrared laser pulses. Moreover, owing to the energy scalability of the advanced DC-OPA scheme, the prospects of the multi-terawatt sub-cycle laser pulses are discussed.

100-mJ class, sub-two-cycle, carrier-envelope phase-stable dual-chirped optical parametric amplification.

Based on dual-chirped optical parametric amplification (DC-OPA) and type-I BiB3O6 (BiBO) crystals, the generation of >100 mJ, 10.4 fs, 10 Hz, carrier-envelope phase (CEP)-stable laser pulses, which are centered at 1.7 µm, was demonstrated producing a peak power of 10 TW. CEP-dependent high harmonic generation (HHG) was implemented to confirm the sub-two-cycle pulse duration and CEP stabilization of infrared (IR) laser pulses. As far as we know, the obtained pulse energy and peak power represented the highest values for sub-two-cycle CEP-stable IR optical parametric amplification. Additionally, the prospects of achieving high-energy water window isolated attosecond pulses (IAPs) via our developed laser source were discussed.

Efficient Generation of Spectrum-Manipulated Few-Cycle Laser Pulses through Cascaded Dual-Chirped OPA.

The cascaded dual-chirped optical parametric amplification (DC-OPA) is presented for efficient generation of few-cycle infrared (IR) laser pulses. The input pulses are strategically chirped to optimize the phase-matching bandwidth in each nonlinear crystal, and four regions of the signal spectrum are amplified in cascaded crystals with different cutting angles, enabling flexible manipulation of the output spectrum. Broadband gain and high conversion efficiency are simultaneously achieved owing to the cascaded-crystal arrangement, the signal pulse duration of 4.2 cycles is obtained with 11.7-mJ pulse energy, corresponding to a conversion efficiency of 39.0%. The proposed scheme offers a robust and simple approach to pushing the phase-matching bandwidth limits introduced by the nonlinear crystal, which manifests great prospect in various researches involving ultrafast optics and strong-field physics.

Dispersed pulses created by aperiodic binary spectral phase jump and applications for pulse shaping.

Inspired by pulse-pair generation with periodic phase jump, the generation of dispersed pulses with aperiodic binary spectral phase jump (ABSPJ) is proposed and theoretically investigated. It is presented by the numerical simulations that two dispersed pulses can be generated by ABSPJ of π. The dispersion of one pulse is opposite to the other and can be tuned freely with engineering of the phase jump. The generated dispersed pulse-pair is potentially of great interest for various applications, such as two-dimensional spectroscopy, double pulses laser-wakefield acceleration (LWFA) and chirp management in dual-chirped optical parametric amplification (DC-OPA) system to generate TW single-cycle mid-infrared (MIR) pulses. Furthermore, a pulse shaper configured as a micro-electro-mechanical systems (MEMS) located at the Fourier plane of a 4-f dispersion-free compressor is suggested and the implementation in a high repetition optical parametric chirped pulse amplification (OPCPA) system with picosecond pump has been numerically studied. The simulations showed that MEMS of 900 pixels is enough to pre-compensate TOD of 200000 fs3 for a pulse of 20 fs. Because pixel with only two piston-levels is necessary for such MEMS, the pulse shaper is expected to be compact and reliable.

Optimization of a multi-TW few-cycle 1.7-µm source based on Type-I BBO dual-chirped optical parametric amplification.

This paper presents the optimization of a dual-chirped optical parametric amplification (DC-OPA) scheme for producing an ultrafast intense infrared (IR) pulse. By employing a total energy of 0.77 J Ti:sapphire pump laser and type-I BBO crystals, an IR pulse energy at the center wavelength of 1.7 µm exceeded 0.1 J using the optimized DC-OPA. By adjusting the injected seed spectrum and prism pair compressor with a gross throughput of over 70%, the 1.7-µm pulse was compressed to 31 fs, which resulted in a peak power of up to 2.3 TW. Based on the demonstration of the BBO type-I DC-OPA, we propose a novel OPA scheme called the "dual pump DC-OPA" for producing a high-energy IR pulse with a two-cycle duration.

Few-cycle 1.9-μm pulse generation via collinear spectrum synthesis in multiple-crystal OPA.

A multiple-crystal optical parametric amplification (OPA) design is reported for efficiently generating few-cycle 1.9-μm laser pulses. Different spectral regions of the idler pulse are successively amplified in three nonlinear crystals with delicately adjusted phase-matching angles, and a broadband spectrum supporting a three-cycle transform-limited (TL) pulse duration is obtained. Near-TL duration of 21.5fs is realized by simple compression in a silicon window. Owing to sufficient exploitation of the pump energy in the crystals, total conversion efficiency of 31.3% is achieved with idler pulse energy of 65.8μJ. The gain bandwidth in multiple-crystal OPA is markedly broadened compared to OPA using a single thick crystal; meanwhile, the high efficiency is preserved. Further energy scaling of the proposed scheme is potentially feasible using dual-chirped OPA geometry.

Dual-Chirped Optical Parametric Amplification: A Method for Generating Super-Intense Mid-Infrared Few-Cycle Pulses

High-energy infrared (IR) femtosecond laser sources are important for applications in ultrafast and strong-field laser science; thus, considerable effort has recently been made to develop such laser systems. In this paper, we review our recent work on developing TW-class mid-infrared (MIR) femtosecond laser pulses in the 1–4 $\mu$ m region using a dual-chirped optical parametric amplification (DC-OPA) method. By employing a Ti:sapphire laser with sub-joule energy to pump the DC-OPA system, MIR femtosecond pulses with 100-mJ-class energy are demonstrated. Efficient energy scalability and flexible wavelength tunability in DC-OPA are confirmed experimentally. Different features of DC-OPA from those of conventional OPA and narrow-band pumped optical parametric chirped pulse amplification (OPCPA) are observed. By precisely optimizing the chirps of the seed and pump pulses in the DC-OPA system, bandwidth narrowing of amplified pulses can be minimized in an energy-scaling strategy. Moreover, DC-OPA can be universally employed for the energy scaling of near-IR, MIR, and far-IR pulses, regardless of the type of nonlinear crystal, and is helpful for efficiently generating few-cycle carrier-envelope phase stable IR pulses with TW-class peak power.

High-energy mid-infrared femtosecond pulses at 3.3 μm directly generated by dual-chirped optical parametric amplification

By employing a dual-chirped optical parametric amplification (DC-OPA) using MgO:LiNbO3 crystals, we generate 31 mJ mid-infrared (MIR) pulses at 3.3 um with a repetition rate of 10 Hz. After passing through a CaF2 bulk compressor which has 70% throughput efficiency, these MIR pulses are compressed to 70 fs (6.3 optical cycles), which is close to the transform-limited duration of 66 fs. Thus, the peak power is evaluated to be 0.3 TW. Our results present notable progress in the generation of high-energy MIR pulses and prove that DC-OPA is a superior method for efficiently generating MIR pulses with few-cycle duration and TW-class peak power.

Towards GW-Scale Isolated Attosecond Pulse Far beyond Carbon K-Edge Driven by Mid-Infrared Waveform Synthesizer

We discuss the efficient generation of intense “water window” (0.28–0.54 keV) isolated attosecond pulses (IAPs) using a mid-infrared (MIR) waveform synthesizer. Our numerical simulations clearly indicate that not only a longer-wavelength driving laser but also a weak control pulse in the waveform synthesizer helps extend the continuum cutoff region and reduce the temporal chirp of IAPs in high-order harmonic generation (HHG). This insight indicates that a single-cycle laser field is not an optimum waveform for generating the shortest IAP from the veiwpoints of reducing the attochirp and increasing the efficiency of HHG. By combining a waveform synthesizer technology and a 100 mJ MIR femtosecond pulse based on a dual-chirped optical parametric amplification (DC-OPA) method, a gigawatt-scale IAP (55 as with 10 nJ order) in the water window region can be generated even without attochirp compensation. The MIR waveform synthesizer is highly beneficial for generating a shorter IAP duration in the soft X-ray region because there are no suitable transparent dispersive materials that can be used for compressing the attochirp.

TW-scale mid-infrared pulses near 3.3 μm directly generated by dual-chirped optical parametric amplification

We report on the generation of a 31 mJ mid-infrared (MIR) pulse with a repetition rate of 10 Hz near 3.3 μm by a dual-chirped optical parametric amplification (DC-OPA) scheme using MgO:LiNbO3 crystals. The MIR pulse is compressed to 70 fs (6.3 optical cycles), which is close to the transform-limited duration of 66 fs, by a CaF2 bulk compressor with 70% throughput efficiency, resulting in 0.3 TW peak power. Our demonstration presents notable progress in the generation of high-energy MIR pulses and proves that DC-OPA is a suitable method for efficiently generating few-cycle MIR pulses with TW-class peak power.

Towards a petawatt-class few-cycle infrared laser system via dual-chirped optical parametric amplification

Expansion of the wavelength range for an ultrafast laser is an important ingredient for extending its range of applications. Conventionally, optical parametric amplification (OPA) has been employed to expand the laser wavelength to the infrared (IR) region. However, the achievable pulse energy and peak power have been limited to the mJ and the GW level, respectively. A major difficulty in the further energy scaling of OPA results from a lack of suitable large nonlinear crystals. Here, we circumvent this difficulty by employing a dual-chirped optical parametric amplification (DC-OPA) scheme. We successfully generate a multi-TW IR femtosecond laser pulse with an energy of 100 mJ order, which is higher than that reported in previous works. We also obtain excellent energy scaling ability, ultrashort pulses, flexiable wavelength tunability, and high-energy stability, which prove that DC-OPA is a superior method for the energy scaling of IR pulses to the 10 J/PW level.

Generation of high-energy narrowband 205 μm pulses for seeding a Ho:YLF laser

We experimentally demonstrate efficient generation of high-energy (82 μJ) narrowband 2.05 μm pulses pumped with 1 mJ broadband Ti:sapphire laser pulses, utilizing dual-chirped optical parametric amplification (DC-OPA) in a BBO crystal. The narrowband 2.05 μm pulses will be primarily used for seeding an Ho:YLF laser, which solves the synchronization issue when Ti:sapphire and Ho:YLF lasers are needed for developing midinfrared lasers. The narrowband 2.05 μm pulse from the unique DC-OPA design can seed the Ho:YLF laser much more efficiently than the broadband 2.05 μm pulse from traditional OPA technology.

Octave-spanning energy-scalable CEP-stabilized pulses from a dual-chirped noncollinear optical parametric amplifier

A dual-chirped noncollinear optical parametric amplification scheme exploiting the unique dispersion properties of BiB3O6 (BiBO) crystal is proposed. Passively CEP-stabilized 2-μm pulses from a broadband pumped OPA are efficiently amplified via noncollinear phase-matching in a thin BiBO crystal, resulting in an octave-spanning spectrum that supports a transform limited duration of 10.1 fs. The proposed scheme shows excellent compressibility and high energy scalability for the output signal. Sub-two-cycle CEP-stable mid-IR pulse with energy exceeding 20 mJ can be expected, which is potentially a perfect driving source in attosecond and strong-field researches.

Periodically intensity-modulated pulses by optical parametric amplification for multicycle tunable terahertz pulse generation

The superposition of signal and idler pulses in dual-chirped optical parametric amplification is proposed for the efficient generation of intensity-modulated pulses with periodic modulation. Both the duration and the modulation period are easily and independently adjustable. Numerical simulations for a three-stage optical parametric amplifier system predicted an efficiency as high as ~50% for about 40 mJ of output pulse energy at a wavelength of 2 µm. Sources of such intensity-modulated pulses near 1.6 µm or 2 µm wavelength, pumped by Ti:sapphire or Yb-doped lasers, can be ideally suited for intense multicycle THz pulse generation with tunable frequency and bandwidth by optical rectification for example in organic, semiconductor, or lithium niobate materials.

Tunable few-cycle pulses from a dual-chirped optical parametric amplifier pumped by broadband laser

We propose a dual-chirped optical parametric amplification (DC-OPA) scheme pumped by a broadband laser pulse. The pump pulse is spectrally broadened in a multi-plate system before amplifying the chirped seed in a BBO crystal. The system performance and phase-matching mechanism with different pump bandwidths are investigated thoroughly. It is found that the broadened pump bandwidth benefits the system most effectively when the pump and seed pulses are oppositely chirped. The idler bandwidth is nearly tripled in the broadband pumped system, supporting a transform-limited (TL) duration of 8.4fs (∼1.3cycles), meanwhile the energy bandwidth product of the idler is 72.6% higher. Furthermore, the idler wavelength is tunable between 1700nm and 2050nm, with sub-1.5-cycle TL duration and over 14% conversion efficiency. The proposed scheme provides a suitable approach for the generation of few-cycle pulses varying from near-infrared to mid-infrared regions.

Energy Scaling of Infrared Femtosecond Pulses by Dual-Chirped Optical Parametric Amplification

We present an energy-scaling experiment on a femtosecond infrared pulse using dual-chirped optical parametric amplification (DC-OPA). A total output energy exceeding 100 mJ with 36-fs pulse duration was achieved in the infrared region, which is the highest energy ever reported for an ultrafast optical parametric amplifier scheme. We also discuss the generation of high-energy 15–30–THz pulses through difference frequency generation between chirped signal and idler pulses based on DC-OPA. By manipulating the phase of a seed pulse in the DC-OPA system, the spectral phase of a THz pulse can be indirectly controlled precisely, which is very helpful for compressing THz pulses.

High-energy two-cycle pulses at 3.2 μm by a broadband-pumped dual-chirped optical parametric amplification.

A design for efficient generation of mid-infrared pulses at 3.2 μm is presented, which is based on numerical simulations of the broadband-pumped dual-chirped optical parametric amplification (DC-OPA) in LiNbO3 doped with 5 mol.% MgO (MgO:LiNbO3). The broadband seed can be generated by difference frequency generation in KTA using spectrally-broadened Ti:Sapphire lasers. The broad DC-OPA phase-matching bandwidth-spanning from 2.4 μm to 4.0 μm-is achieved by chirping both the broadband Ti:Sapphire pump pulses and the seed pulses in such a way that the individual temporal slice of pump spectrum is able to phase match that of seed spectrum. This phase matching scheme allows the use of longer crystals without gain narrowing or loss of conversion efficiency. The theoretical conversion efficiency from the pump to the idler reaches 19.1 %, enabling generation of a few hundred mJ of mid-IR energy with an available large-aperture MgO:LiNbO3 crystal. Furthermore, the commercially available acousto-optic programmable dispersive filter (AOPDF) ensures compression of such a broad bandwidth down to 20 fs (two optical cycles at 3.2 μm).

Bandwidth control in 5 μm pulse generation by dual-chirped optical parametric amplification

We extend the technique of difference-frequency mixing of broadband chirped near-infrared (IR) pulses to longer wavelengths, thereby generating high-energy, bandwidth-tunable laser pulses in the mid-IR spectral region. Numerical modeling has been performed to examine the influence of pump and seed chirp on the generated idler bandwidth and pulse duration. The amplifier is realized using zinc-germanium phosphide crystals pumped by a 2 μm ultrafast parametric source. Idler pulses at a center wavelength of 5 μm with adjustable bandwidth are produced by equally chirping the pump and seed pulses using material dispersion. Using this simple approach, efficient generation of narrowband, short, mid-IR laser pulses is achieved without the use of high-loss dispersive gratings or prism pairs.