YAG Innoslab Research Articles

80-W single-frequency Innoslab µs-amplifier at 1319 nm with high efficiency.

A single-frequency quasi-continuous-wave partially end-pumped slab (Innoslab) laser amplifier at 1319 nm was demonstrated. The 3-W single-frequency all-fiber seed laser was amplified to a maximum average power of 80.1 W and the power stability was 0.52% in 10 minutes. The corresponding optical-optical efficiency was 16.1% under absorbed pump power of 478 W. The output pulse width was 131 µs at the repetition of 500 Hz. The beam quality factors of M2 were 1.3 in both the vertical and horizontal directions. To the best of our knowledge, this is the first report on single-frequency Nd:YAG Innoslab amplifier at 1319 nm with such high output power and efficiency.

210-W, Quasi-Continuous Wave, Nd:YAG InnoSlab Laser at 1319 nm

In this paper, we demonstrate a high-power, quasi-continuous wave using a laser-diode dual-end-pumped Nd:YAG InnoSlab laser at 1319 nm. The maximum average output power of 210 W at a single 1319 nm wavelength is obtained with an optical-optical efficiency of 18.8% from absorbed pump power to laser output. The output pulse duration is 246 μs at the repetition of 500 Hz, and the beam quality factors of M2 are 1.37 and 1.47 in the horizontal and vertical directions, respectively. This is the first report on high-power, quasi-continuous wave using Nd:YAG InnoSlab lasers at 1319 nm with good beam quality.

170-W Nd:YAG InnoSlab laser at 1319 nm.

In this paper, a continuous-wave Nd:YAG InnoSlab laser at 1319 nm with high output power and high beam quality is demonstrated. The maximum output power of 170 W at 1319-nm single wavelength is obtained with an optical-to-optical efficiency of 15.3% from absorbed pump power to laser output and the corresponding slope efficiency of 26.7%. The beam quality factors of M2 are 1.54 and 1.78 in the horizontal and vertical directions, respectively. To the best of our knowledge, this is the first report on Nd:YAG 1319-nm InnoSlab lasers with such high output power and good beam quality.

LD End-Pumped Nd:YAG InnoSlab Laser at 1319 nm

The 1319 nm lasers have important research value and application prospects in optical communications, biomedicine and nonlinear frequency conversion. Currently, there are few reports of high power 1319 nm continuous lasers with high beam quality. We have demonstrated a high output power, high beam quality 1319 nm continuous-wave laser by laser diode end-pumped Nd:YAG slab with a stable-unstable hybrid resonator. With a pumping power of 477 W, an output of 96.8 W was obtained with a slope efficiency of 26.5% and stability of 0.27%. A single wavelength laser operation at 1318.7 nm was demonstrated. At an output of 91.1 W, the beam quality factors M2 in stable and unstable directions were 2.95 and 1.88, respectively.

High power diode end-pumped 1.3 μm Nd:YAG InnoSlab laser

We reported a simple, compact 1.3 μm diode end-pumped 0.6-at.% Nd:YAG InnoSlab laser. The crystal was placed in a stable spherical plano-concave resonator. The laser performance was optimized using output couplers with transmission T = 5% and T = 10% at various cavity lengths. For the cavity length of 40 mm, the maximum output power of 23.2 W was obtained at T = 5%. The laser achieved 17.8% slope efficiency and 11.36% optical conversion efficiency.

High efficiency, 41.6 W, 10 kHz picosecond output based on a Nd:YAG double-pass multi-folded Innoslab amplifier

We designed a novel structure of double-pass multi-folded partially-end-pumped slab (Innoslab) amplifier, which could effectively improve the extraction efficiency. High efficiency and high power picosecond (ps) radiation was obtained by the Nd:YAG Innoslab amplifier. A 4.5 W seed at a repetition rate of 10 kHz was amplified to 41.6 W under an absorbed pump power of 124.7 W, corresponding to extraction efficiency of 29.8%. The pulse duration was approximately 86.5 ps, and the corresponding peak power was up to 48.1 MW. The beam quality factor M2 at the maximum output power was measured to be 2.28 and 1.52 in the horizontal and vertical directions, respectively. To the best of our knowledge, this study was the first to report high efficiency double-pass multi-folded Innoslab amplifier.

148-W single-frequency Nd:YAG Innoslab μs-amplifier at 1064 nm with high efficiency.

In this paper, a single-frequency quasi-continuous-wave partially pumped slab (Innoslab) amplifier at 1064 nm is reported. The 4.4-W single-frequency seed laser was amplified to 148.1 W with optical-optical efficiency of 30.4%. The output pulse duration was 141.4 μs at the repetition of 500 Hz. The beam quality factors of M2 were 1.41 and 1.37 in the horizontal and vertical direction respectively. The experimental results match well with the numerical simulation. To the best of our knowledge, this is the first report on single-frequency Nd:YAG Innoslab amplifier with such a high output power and efficiency.

300 W two-stage Nd:YAG Innoslab microsecond amplifier.

In this paper, a two-stage partially pumped slab (Innoslab) microsecond amplifier at 1064 nm is reported. The 4.4-W single-frequency seed laser is amplified to 303.6 W, with an overall optical-optical efficiency of 25.7%. The overlapping efficiency of the first- and second- amplifier stage is 67% and 55.6%, respectively. The pulse width is 145.0 µs, at a repetition rate of 500 Hz, and the beam quality factor of M2 is 1.84 and 1.71 in the horizontal and vertical directions, respectively. With higher overlap between the pump volume and the seed laser mode, the output power and optical-optical efficiency can be further improved.

20 W, 2 mJ, sub-ps, 258 nm all-solid-state deep-ultraviolet laser with up to 3 GW peak power.

We demonstrate an all-solid-state deep-ultraviolet (DUV) laser based on the frequency-quadrupling of a 1 µm, 1.2 ps, Yb: YAG Innoslab solid-state laser at a 10 kHz repetition rate, using LBO and BBO as second-harmonic generation and fourth-harmonic generation crystals, respectively. The DUV laser delivers 20 W, 2.0 mJ, 665 fs, 258 nm DUV pulses, with an overall conversion efficiency of ∼8.7% from 1 µm to DUV. The corresponding peak power of DUV pulses is up to 3 GW, which, to the best of our knowledge, is highest in reported kHz-rate all-solid-state DUV sources driven at 1 µm wavelength.

High average power 88 W OPCPA system for high-repetition-rate experiments at the LCLS x-ray free-electron laser.

We present a 100kHz, sub-20fs optical parametric chirped-pulse amplifier (OPCPA) system delivering 88.6W average power at a center wavelength of 800nm. The seed pulses are derived from the pump laser via white-light continuum generation and are amplified in three non-collinear OPCPA stages. The final two high-power stages are pumped with a 661W Yb:YAG InnoSlab amplifier. A simple and robust design is used for the OPCPA system to avoid thermal effects and enhance long-term stability, resulting in excellent beam quality and high conversion efficiency. To the best of our knowledge, this is the highest average power OPCPA system reported to date.

43 W, 1.55 μm and 12.5 W, 3.1 μm dual-beam, sub-10 cycle, 100 kHz optical parametric chirped pulse amplifier.

We present a 100 kHz optical parametric chirped pulse amplifier (OPCPA) developed for strong-field attosecond physics and soft-x-ray transient absorption experiments. The system relies on noncollinear potassium titanyl arsenate booster OPCPAs and is pumped by a 244 W, 1.1 ps Yb:YAG Innoslab chirped pulse laser amplifier. Two optically synchronized infrared output beams are simultaneously available: a 430 μJ, 51 fs, carrier-envelope phase stable beam at 1.55 μm and an angular-dispersion-compensated, 125 μJ, 73 fs beam at 3.1 μm.

Near-diffraction-limited diode end-pumped 2 µm Tm:YAG Innoslab laser

A compact, near-diffraction-limited laser diode end-pumped 2 µm Tm:YAG Innoslab laser was demonstrated for the first time. A maximum output power of 36.4 W was achieved under the incident pump power of 184 W, corresponding to a slope efficiency of 23.4% with respect to the incident pump power. The beam quality factors M2 were measured to be 1.44 in the stable direction and 1.23 in the unstable direction.

Near-diffraction-limited 156 W laser-diode end-pumped Yb:YAG Innoslab laser operated at room temperature

We report our findings on laser-diode end-pumped Yb:YAG slab output characteristics when using a compact positive confocal unstable–stable hybrid resonator at room temperature. Preliminary experimental results show that for an absorbed pump power of 680 W, a maximum output power of 156 W was produced at 1030 nm with a stability of 0.9%. An optical-to-optical efficiency of 22.9% and slope efficiency of 37.1% were obtained, and the beam quality M 2 factors in the unstable and stable direction were 1.04 and 1.01, respectively.

High-Efficiency 2-mJ 5-kHz Picosecond Green Laser Generation by Nd:YAG Innoslab Amplifier

A high-efficiency picosecond (ps) 532-nm green laser with high pulse energy and high peak power at 5-kHz repetition rate was demonstrated by second-harmonic generation (SHG) from a 1064-nm master oscillator power amplifier (MOPA). The MOPA was based on the Innoslab structure under diode directly pumping, producing 4.8-mJ, 25-ps fundamental laser at the repetition rate of 5 kHz after a three-stage Innoslab amplification system. With a pulse energy of 2.93 mJ in the fundamental and using a type I noncritically phase matched lithium triborate crystal, the pulse energy of SHG was up to 1.96 mJ per pulse with a pulse width of 18.9 ps, which corresponds to a peak power of 104 MW in the green and SH conversion efficiency as high as 67%. The SHG green beam quality factor was measured to be $M^{2} = 1.75$ .

500 kHz OPCPA delivering tunable sub-20 fs pulses with 15 W average power based on an all-ytterbium laser.

An optical parametric chirped pulse amplifier fully based on Yb lasers at 500 kHz is described. Passive optical-synchronization is achieved between a fiber laser-pumped white-light and a 515 nm pump produced with a 200 W picosecond Yb:YAG InnoSlab amplifier. An output power up to 19.7 W with long-term stability of 0.3% is demonstrated for wavelength tunable pulses between 680 nm and 900 nm and spectral stability of 0.2%; 16.5 W can be achieved with a bandwidth supporting 5.4 fs pulses. We demonstrate compression of 30 µJ pulses to sub-20 fs duration with a prism compressor, suitable for high harmonic generation.

Power scaling of supercontinuum seeded megahertz-repetition rate optical parametric chirped pulse amplifiers

Optical parametric chirped-pulse amplifiers with high average power are possible with novel high-power Yb:YAG amplifiers with kW-level output powers. We demonstrate a compact wavelength-tunable sub-30-fs amplifier with 11.4W average power with 20.7% pump-to-signal conversion efficiency. For parametric amplification, a beta-barium borate crystal is pumped by a 140W, 1ps Yb:YAG InnoSlab amplifier at 3.25MHz repetition rate. The broadband seed is generated via supercontinuum generation in a YAG crystal.

Single-pass high-harmonic generation at 208 MHz repetition rate

We report on single-pass high-harmonic generation (HHG) with amplified driving laser pulses at a repetition rate of 20.8 MHz. An Yb:YAG Innoslab amplifier system provides 35 fs pulses with 20 W average power at 1030 nm after external pulse compression. Following tight focusing into a xenon gas jet, we observe the generation of high-harmonic radiation of up to the seventeenth order. Our results show that state-of-the-art amplifier systems have become a promising alternative to cavity-assisted HHG for applications that require high repetition rates, such as frequency comb spectroscopy in the extreme UV.

Yb:YAG Innoslab amplifier: efficient high repetition rate subpicosecond pumping system for optical parametric chirped pulse amplification

We report on a Yb:YAG Innoslab laser amplifier system for generation of subpicsecond high energy pump pulses for optical parametric chirped pulse amplification (OPCPA) at high repetition rates. Pulse energies of up to 20 mJ (at 12.5 kHz) and repetition rates of up to 100 kHz were attained with pulse durations of 830 fs and average power in excess of 200 W. We further investigate the possibility to use subpicosecond pulses to derive a stable continuum in a YAG crystal for OPCPA seeding.

Compact diode-pumped 11 kW Yb:YAG Innoslab femtosecond amplifier

We demonstrate a compact diode-pumped Yb:KGW femtosecond oscillator-Yb:YAG Innoslab amplifier master oscillator power amplifier (MOPA) with nearly transform-limited 636 fs pulses at 620 W average output power, 20 MHz repetition rate, and beam quality of M(x)(2) = 1.43 and M(y)(2) = 1.35. By cascading two amplifiers, we attain an average output power of 1.1 kW, a peak power of 80 MW, and a 615 fs pulse width in a single linearly polarized beam. The power-scalable MOPA is operated at room temperature, and no chirped-pulse amplification technique is used.

400W Yb:YAG Innoslab fs-Amplifier

The Innoslab design, already established for neodymium doped laser crystals, was applied to ytterbium doped laser materials. Recent progresses in brightness of high power diode lasers facilitate efficient pumping of quasi-three-level laser materials. Innoslab amplifiers are compared to competing thin-disk and fiber fs-amplifiers. A compact diode-pumped Yb:YAG Innoslab fs-oscillator-amplifier system, scalable to the kilowatt range, was realized. Numerical simulations result in conditions for high efficiency and beam quality. Nearly transform and diffraction limited 680 fs pulses at 400 W average output power and 76 MHz repetition rate without using CPA technology have been achieved at room temperature so far.