A few‐cycle, broadband, singly‐resonant optical parametric oscillator (OPO) for the mid‐infrared based on MgO‐doped periodically‐poled LiNbO3 (MgO:PPLN), synchronously pumped by a 20‐fs Ti:sapphire laser is reported. By using crystal interaction lengths as short as 250 µm, and careful dispersion management of input pump pulses and the OPO resonator, near‐transform‐limited, few‐cycle idler pulses tunable across the mid‐infrared have been generated, with as few as 3.7 optical cycles at 2682 nm. The OPO can be continuously tuned over 2179‐3732 nm (4589‐2680 cm‐1) by cavity delay tuning, providing up to 33 mW of output power at 3723 nm. The idler spectra exhibit stable broadband profiles with bandwidths spanning over 422 nm (FWHM) recorded at 3732 nm. The effect of crystal length on spectral bandwidth and pulse duration is investigated at a fixed wavelength, confirming near‐transform‐limited idler pulses for all grating interaction lengths. By locking the repetition frequency of the pump laser to a radio‐frequency reference, and without active stabilization of the OPO cavity length, an idler power stability better than 1.6% rms over >2.75 hours is obtained when operating at maximum output power, in excellent spatial beam quality with TEM00 mode profile. Photograph shows a multigrating MgO:PPLN crystal used as a nonlinear gain medium in the few‐cycle femtosecond mid‐IR OPO. The visible light is the result of non‐phase‐matched sum‐frequency mixing between the interacting beams. 相似文献
We report a femtosecond optical parametric oscillator (OPO) based on the nonlinear material BiB3O6. The OPO is synchronously pumped in the blue by the second harmonic of a Kerr-lens-mode-locked Ti:sapphire laser. It can provide wide and continuous tuning across the entire green-yellow-orange-red spectral range with a single crystal and a single set of mirrors. Using a 500 microm BiB3O6 crystal and collinear type I (e+e->o) phase matching in the optical yz plane, a signal wavelength range of 480-710 nm is demonstrated with angle tuning at room temperature at average output powers of 270 mW. With 220 fs blue pump pulses, near-transform-limited signal pulses of 120 fs duration have been obtained at 76 MHz repetition rate. 相似文献
We report efficient generation of tunable femtosecond pulses in the ultraviolet (UV) by intracavity doubling of a visible femtosecond optical parametric oscillator (OPO). The OPO, based on a 400 microm BiB3O6 crystal and pumped at 415 nm in the blue, can provide visible femtosecond signal pulses across 500-710 nm. Using a 500 microm crystal of beta-BaB2O4 internal to the OPO cavity, efficient frequency doubling of the signal pulses into the UV is achieved, providing tunable femtosecond pulses across 250-355 nm with up to 225 mW of average power at 76 MHz. Cross-correlation measurements result in UV pulses with durations down to 132 fs for 180 fs blue pump pulses. 相似文献
We report an efficient laser emission on the 912 nm 4F3/2 to 4I9/2 transition in Nd:GdVO4 under the pump with diode lasers at 888 nm. Continuous wave (CW) 4.91 W output power at 912 nm is obtained under 18.3 W of
incident pump power; the slope efficiency with respect to the incident pump power was 57.5%. Moreover, intracavity frequency
doubling with BiB3O6 (BiBO) nonlinear crystal yielded 1.33 W of deep-blue light at 456 nm. 相似文献
We report the phase matching of parametric frequency conversion in the nonlinear material BiB3O6 (BiBO) and on an investigation of optical parametric oscillators (OPOs) of this new crystal. Based on the calculation of collinear type I and type II phase matching within the refractive-index planes, the most favorable directions for phase matching are identified for OPOs pumped by the fundamental or the harmonics of 1064-nm Nd-doped lasers. Based on these results, pulsed 532-nm-pumped ns OPOs are realized. The pump source is either a Q-switched high repetition rate (10 kHz) Nd:YVO4 laser (with a pulse energy of 24 J) or a low repetition rate (10 Hz), high pulse energy (120 mJ) Nd:YAG laser system. The BiBO OPO pumped by the Nd:YVO4 laser showed a very low threshold of 0.047 J/cm2. At an average pump power of 2.4 W the total OPO output power was 630 mW. By changing the phase-matching angle within the yz plane from 0 to 11.6° the signal wavelength was tuned from 735 nm to 970 nm, while the spectral width changed from 0.2 nm to 1.4 nm. By pumping the OPO with the Nd:YAG laser, the OPO had a threshold of 0.12 J/cm2, a steep slope (59%) and a high total efficiency (of up to 48%). Due to divergence broadening the spectral width changes from 8.5 nm at 800 nm to 70 nm near degeneracy. The properties of BiBO determined from the experimental results are compared with those of well-known nonlinear materials such as BBO, LBO and KTP. PACS 42.65.-k; 42.65.Yj; 42.70.-a; 42.70.Mp 相似文献
We report efficient laser emission on the 914 nm 4F3/2 to 4I9/2 transition in Nd:YVO4 under the pump with diode lasers at 888 nm for the first time. Continuous wave 6.57 W output power at 914 nm is obtained
from a V-type resonator under 18.3 W of absorbed pump power; the slope efficiency with respect to the absorbed pump power
was 60.6%. Moreover, intracavity frequency doubling with BiB3O6 (BiBO) nonlinear crystal yielded 1.77 W of deep-blue light at 457 nm with beam quality characterized by an M2 factor of 1.25. 相似文献
We report on an idler-resonant femtosecond optical parametrical oscillator(OPO)based on BiB3O6(BiBO)crystal,synchronously pumped by a frequency-doubled,mode-locked Yb:KGW laser at 515 nm.The idler wavelengths of OPO can be tuned from 1100 nm to 1540 nm.At a repetition rate of 75.5 MHz,the OPO generates as much as 400 mW of idler power with 3.1 W of pump power,the corresponding pulse duration is 80 fs,which is 1.04 times of Fourier transform-limited(FTL)pulse duration at 1305 nm.In addition,the OPO exhibits excellent beam quality with M2<1.8 at 1150 nm.To the best of our knowledge,this is the first idler-resonant femtosecond OPO pumped by 515 nm. 相似文献
We report a high‐repetition‐rate picosecond fiber‐based source at 2.1 µm offering exceptional performance capabilities over existing lasers near this wavelength, providing high average power and efficiency together with excellent spectral, power and beam pointing stability, in high spatial beam quality. This new source is based on a near‐degenerate MgO:PPLN optical parametric oscillator (OPO) pumped by an Yb‐fiber laser at 1064 nm, and incorporating a diffraction grating for spectral control. The device provides as much as 7.1 W of average power at 2.1 µm for a pump power of 18 W at an extraction efficiency of 39.4% in pulses of 20 ps at 79.3 MHz. The output exhibits passive power stability better than 1% rms over 15 hours, and a beam pointing stability ∼40 µrad over 1 hour, in high spatial quality with M2 ∼ 3.5. The output beam is linearly polarized and the pulse train has an amplitude stability better than 3.4% rms over 2 µsec. Radio‐frequency measurements of the output pulse train also confirm high temporal stability and low timing jitter, indicating that the source is ideal for variety of applications including pumping long‐wavelength mid‐infrared OPOs. Photograph shows the temperature‐controlled, 50‐mm‐long MgO:PPLN crystal inside the cavity, used as nonlinear gain medium in the picosecond source operating at 2.1 µm. The visible light is the result of non‐phase‐matched second harmonic generation of the pump beam in the MgO:PPLN crystal.
We demonstrated experimentally a synchronously pumped intracavity frequency-doubled femtosecond optical parametric oscillator (OPO) using a periodically-poled lithium niobate (PPLN) as the nonlinear material in combination with a lithium triborate (LBO) as the doubling crystal. A Kerr-lens-mode-locked (KLM) Ti:sapphire oscillator at the wavelength of 790 nm was used as the pump source, which was capable of generating pulses with a duration as short as 117 fs. A tunable femtosecond laser covering the 624-672 nm range was realized by conveniently adjusting the OPO cavity length. A maximum average output power of 260 mW in the visible range was obtained at the pump power of 2.2 W, with a typical pulse duration of 205 fs assuming a sech2 pulse profile. 相似文献
We report a femtosecond optical parametric oscillator (OPO) based on the nonlinear material BiB?O? (BIBO) pumped directly by a Kerr lens mode-locked Ti:sapphire laser. Using a 1.5 mm long BIBO crystal cut at θ=11.4° for collinear type I (e→o+o) phase matching in the xz optical plane, femtosecond signal pulses across 1.4-1.6 μm, and idler pulses across 1.6-1.87 μm spectral range are generated, limited by the reflectivity bandwidth of the OPO mirrors. The high nonlinear gain and large spectral acceptance for type I interaction in the xz plane of BIBO permit rapid and continuous tuning across the entire range by simple fine adjustment of OPO cavity delay or through small changes in the pump wavelength, without varying any other parameters. Additionally, owing to the near-zero group velocity mismatch and dispersion, the OPO supports broad spectrum as wide as 33 nm, which results in self-compressed signal pulses. For 150 fs pump pulses, signal pulses with durations down to 106 fs with a time-bandwidth product of 0.48 are obtained without the need for intracavity dispersion compensation. 相似文献
Efficient generation of femtosecond pulses in the wavelength range from 520 to 675 nm by external frequency doubling the signal wave of a non-critically phase-matched picosecond KTP Optical Parametric Oscillator (OPO) in a non-critically phase-matched temperature tuned LiB3O5(LBO) crystal is demonstrated. An average power of the second harmonic as high as 310 mW at 575 nm was generated. In the absence of group velocity mismatch of LBO for a wavelength of the OPO at about 1.3 µm the minimum second-harmonic pulse width was 400 fs at 645 nm. 相似文献
Five‐cycle (50 fs) mid‐IR pulses at 80‐MHz repetition rate are produced using a degenerate (subharmonic) optical parametric oscillator (OPO), synchronously pumped by an ultrafast 1560‐nm fiber laser. The effects of cavity dispersion and the length of a periodically poled lithium niobate (PPLN) gain element on the output spectrum and pulse duration are investigated by taking advantage of a very broad (∼ 1000 cm−1) gain bandwidth near the 3.1‐μm OPO degeneracy point. A new method of assessing the total OPO group delay dispersion across its entire spectrum is proposed, based on measuring spectral signatures of trace amounts of molecular gases injected into the OPO cavity. 相似文献
Efficient CW intracavity frequency doubling of a diode-end-pumped Nd:GGG laser operating on 4F3/2 → 4I9/2 transitions at 937 nm has been demonstrated. A 10-mm-long BiB3O6(BiBO) crystal, cut for critical type I phase matching, was used for the intracavity frequency doubling of the laser. A maximum
output power of 350 mW in the blue spectral range at 469 nm has been achieved at 18.3 W of pump power. The M2 factors are 1.18 and 1.29 in X and Y directions, respectively. 相似文献
A high‐power femtosecond Yb:fiber system is seeded by a phase‐locked Er:fiber source and drives an ultra‐broadband optical parametric amplifier that operates at 10 MHz repetition rate. The resulting pulses display precise control of the carrier‐envelope phase. Their 8.3 fs temporal duration corresponds to 2.3 optical cycles of the 1100 nm carrier wavelength. Focusing 200 nJ of pulse energy into widegap materials generates optical harmonics up to fifth order. Even in a perturbative regime, strong effects of the carrier‐envelope phase on the emitted spectra are observed. 相似文献
It is reported that efficient continuous-wave (CW) blue laser generation at 465 nm in a BiB3O6 (BiBO) crystal at type-I phase matching direction performed with a diode-pumped Nd3+:YAlO3 (Nd:YAP) laser. With incident pump power of 18.4 W, output power of 823 mW at 465 nm has been obtained using a 10 mm-long
BiBO crystal. At the output power level of 823 mW, the output stability is better than 2.3%. 相似文献
The defect chalcopyrite crystal HgGa2S4 has been employed in a 1064‐nm pumped optical parametric oscillator operating at 100 Hz, to generate ∼5 ns long idler pulses near 4 µm with energies as high as 6.1 mJ and average power of 610 mW. At crystal dimensions comparable to those available for the commercial AgGaS2 crystal, operation of the 1064‐nm pumped HgGa2S4 OPO is characterized by much lower pump threshold and higher conversion efficiency, with the most important consequence that such a device might become practical at pump levels sufficiently lower than the optical damage threshold. 相似文献