Intense pulse pumped microlaser is proposed for high peak power and low timing jitter at high repetition rate. It is based on Intense and Fast Pulse Pump (IFPP) technique, in which fast pulse pumps ...up the upper-level population and then dumps it rapidly by Q-switching. That could come close to complete pumping efficiency to reduce thermal problems and contribute to suppress the timing jitter of passively Q-switched laser. In this work, linearly polarized 1064 nm beam from 100-cut YAG/Nd3+:YAG and 110-cut Cr4+:YAG passively Q-switched microlaser is directly guided into nonlinear crystals to obtain 532 nm and 266 nm output. By implementing IFPP concept, over 1 MW peak power, 215 ps pulse duration, 1 kHz pulses at 266 nm with reduced standard deviation timing jitter of 37 ns were obtained.
The passive Q-switching characteristics of a diode-pumped Tm,Ho:YAP laser at 2 μm based on a MoS 2 saturable absorber (SA) is presented for the first time. Pulses as short as 435 ns under a ...repetition rate of about 55 kHz were generated at the incident pump power of 8.4 W, corresponding to the pulse peak power up to 11.3 W. This is, to the best of our knowledge, the highest pulse peak power, ever obtained from MoS 2 based passively Q-switched 2-μm lasers. The experimental results sufficiently validated the feasibility of MoS 2 as SA for solid-state 2-μm lasers.
Shape design of sapphire/Nd3+:YAG based distributed face cooling (DFC) chip is reported with reduction of thermal effects as compared with those from a conventional Nd3+:YAG chip. The CW diode laser ...pumped round-trip cavity loss was 0.51% from a 9-disk bonded DFC chip, which was close to the theoretically calculated total Fresnel reflection loss of 0.2% from 8 Sapphire/Nd3+:YAG interfaces. The depolarization ratio from an 8-disk bonded DFC chip was 40 times lower than that from YAG/Nd3+:YAG chip. The DFC chip underwent no crack at pump power of 86 W while Nd3+:YAG single chip suffered crystal crack under pump power around 54 W. Over megawatt peak power from DFC tiny integrated laser is demonstrated at 1 kHz with 3-pulse burst modes. It is concluded that DFC structure could relieve thermal effects as expected.
Both tunable and passively mode-locked laser oscillators based on an efficient Yb,Gd:SrF 2 crystal are reported for the first time. Charge compensation ions of Gd 3+ enhanced the emission and ...absorption cross section of Yb,Gd:SrF 2 crystal markedly. With the aid of birefringent filter, a 61.1-nm continuous-wavelength-tunable laser from 1020.2 to 1081.3 nm was obtained, making it a potential candidate for ultrafast lasers. Based on a semiconductor saturable absorber mirror, a diode-pumped passively mode-locked laser with the pulse width of 951 fs was realized. The oscillator operated at a repetition rate of 92 MHz.
A kind of saturable absorber (SA) based on layered MoSe 2 nanosheets has been fabricated successfully by an ultrasound-assisted liquid phase exfoliation method. The as-prepared MoSe 2 SA was ...characterized and employed as Q-switch in a diode-pumped Tm-doped crystalline all-solid-state laser at around 2 μm. A stable passively Q-switched 2 μm laser with a maximum pulse repetition rate of 158 kHz and a minimum pulse width of 520 ns was successfully realized. A maximum average output power of 1.19 W, corresponding to a maximum pulse energy of 12.7 μJ and pulse peak power of 21.8 W, has been obtained. It was the first demonstration of MoSe 2 SA in realizing a solid-state 2 μm pulsed laser, to the best of our knowledge. The results confirmed the excellent ability and promising potential of MoSe 2 SA as an optical modulator in generating high repetition rate and short pulsed laser at the midinfrared spectral band.
By transferring the colloidal suspensions of ferroferric-oxide (Fe 3 O 4 ) nanoparticles (FONPs) onto a quartz plate, zero-dimension FONPs saturable absorber (SA) is successfully fabricated and ...employed in a Tm:Lu 3 Al 5 O 12 (Tm:LuAG) bulk laser. The properties of the FONPs-SA including Raman response, nonlinear optical response, and broad-band spectral absorption from 1800 nm to 2500 nm are measured. With the as-prepared FONPs-SA, laser pulses with the shortest duration of 600 ns, a maximum repetition rate of 96 kHz and maximum pulse energy of 4.9 μJ are obtained, corresponding to a maximum peak power of 8.2 W. This is the first experimental demonstration of the zero-dimension FONPs-SA as Q-switch in 2 μm spectral region and even longer wavelength mid-infrared spectral region, to the best of our knowledge, which indicates that the zero-dimension FONPs-SA can act as a promising optical modulator in mid-infrared spectral region.
Dy3+-doped CaF2-SrF2 crystals with various Dy3+ dopant concentrations were synthesized by multicrucible temperature gradient technology (MC-TGT). Dy:CaF2-SrF2 crystals were fluorite structured and ...crystallized in cubic Fm3¯m space group, as characterized by X-ray diffraction. The crystallographic site concentration was calculated from the measured density by Archimedes’ hydrostatic weighing principle. The optical transmission reached over 90% with a sample thickness of 1.0 mm. The Sellmeier dispersion formula was obtained following the measured refractive index in a mid-IR range of 1.7–11 μm. Absorption coefficients of 6.06 cm−1 and 12.71 cm−1 were obtained at 804 nm and 1094 nm in 15% Dy:CaF2-SrF2 crystal. The fluorescence spectra of 15 at.% Dy:CaF2-SrF2 showed the strongest wavelength peak at 2919 nm with a full width at half maximum (FWHM) of 267 nm under an excitation wavelength of 808 nm. The fluorescence lifetimes were illustrated for different Dy3+ dopant levels of 5%, 10% and 15%. The results indicate that the Dy:CaF2-SrF2 crystal is a promising candidate for compact mid-IR lasers.
We report both continuous-wave and passively mode-locked laser actions in a Yb 3+ -doped gadolinium yttrium oxyorthosilicate Yb:GdYSiO 5 (Yb:GYSO) crystal. Continuous-wave (CW) laser operations were ...compared under different pump conditions with high-power diodes of different wavelengths and fiber cores. CW mode-locking was obtained with a semiconductor saturable absorber mirror.
•Nd,Y:CaF2 crystals with diameter 3-inch were grown by TGT method.•Optical spectra of Nd,Y:CaF2 crystals were recorded at different temperatures.•Broad and flat emission spectra of Nd3+ ions were ...obtained by Y3+-codoping.
High optical quality Nd,Y-codoped CaF2 crystals with diameter 3-inch were obtained by TGT method. Absorption and emission spectra were recorded at 5K, 12K, and 300K respectively. Judd–Ofelt theory was applied to obtain standard parameter Ωt (t=2, 4, 6) and the fitting result of experimental lifetime of Nd3+4F3/2→4I11/2 transition. Broad and flat 1.06μm emission spectra of Nd3+ ions were obtained with Y3+-codoping. The largest emission bandwidth of Nd3+4F3/2→4I11/2 transition is up to 28nm. The results revealed that codoping Y3+ ions in Nd:CaF2 crystal can effectively modulate the spectra properties of Nd3+ ions, in addition to the reduction of fluorescence concentration-quenching.
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