Based on non-collinear phase-matching (PM), a new method for widely tunable wavelength was proposed and demonstrated in a four-mirror ring cavity of non-critical phase-matching (NCPM) KTiOAsO
4
(KTA) ...optical parametric oscillator (OPO). Wavelength tuning range of 141 nm from 1535.56 nm to 1676.73 nm was achieved by moving one mirror of ring cavity back and forth. The tuning theory and tuning method of non-collinear PM were analyzed in detail. The output energy and pulse width of signal were measured and compared in collinear and non-collinear PM condition. This method is also applicable to OPOs of other nonlinear crystals based on four-mirror ring cavity.
A 1064-nm femtosecond fiber chirped pulse amplification (FCPA) laser system based on a single-stage double-pass Yb-doped rod-type photonic crystal fiber (PCF) amplifier was demonstrated with a pulse ...repetition rate of 500 kHz, which was specially designed for expected conversion efficiency enhancement of a 10.8 eV source. With a series of Yb:fiber power amplifiers, the average output power was boosted to approximately 35 W. Further, using a transmission gratings-based pulse compressor, an average output power of 27.5 W was achieved, corresponding to a pulse energy of 55 µJ and a compression efficiency of 78.6%. The shortest pulse duration was optimized to be 204 fs, which was also accompanied by obvious pedestal. A pulse duration of 336 fs was also obtained when the pulse quality was at a top priority. To the best of our knowledge, this is the first demonstration of high-repetition-rate high-pulse-energy 1064-nm, instead of 1035-nm, femtosecond laser, based on commercially available Yb-doped rod-type PCF amplifier.
A high efficiency, continuous-wave, narrow linewidth, pump-enhanced optical parametric oscillator (OPO) at 3.8 µm was demonstrated, which was pumped by a 1064 nm fiber laser with a linewidth of 18 ...kHz. The low frequency modulation locking technique was employed to stabilize the output power. The wavelengths of signal and idler were 1475.5 nm and 3819.9 nm at 25 °C, respectively. The pump-enhanced structure was applied, leading to a maximum quantum efficiency of over 60% with pump power of 3 W. The maximum output power of idler light is 1.8 W with a linewidth of 363 kHz. The excellent tuning performance of the OPO was also demonstrated. In order to avoid mode-splitting and decrease of pump enhancing factor due to feedback light in the cavity, the crystal was placed obliquely to the pump beam and the maximum output power was increased by 19%. At the maximum output power of idler light, the M
factors in the x and y directions were 1.30 and 1.33, respectively.
In this paper, we demonstrate a 570.0 MHz harmonically mode-locked all-polarization-maintaining Ho-doped fiber laser based on semiconductor saturable absorbed mirror. Firstly, the laser operates in ...the 15.4 MHz fundamental mode-locked soliton regime, emitting 2051.5 nm, 1.62 ps soliton pulse without Kelly sidebands. And then, the stable 37th-order harmonic mode-locked soliton with maximum repetition rate up to 570.0 MHz at 2053nm is generated. Moreover, colorful soliton rain behaviors are also discussed.
A high-repetition-frequency side-pumped electro-optical (E-O) Q-switched Nd:YAG laser without water cooling is reported. A 100 Hz laser module without water-cooling was designed and the related ...parameters of crystal are simulated. The crystal is annularly pumped in both ends and is conductively cooled in the middle. The heat generated by crystal and laser diode is dissipated by thermoelectric cooler (TEC), fins and fan. The 1064 nm maximum output energy is 68 mJ with a pulse width of 31 ns and a repetition rate of 100 Hz. The optical–optical conversion efficiency is 10.6%. To the best of our knowledge, this is the first report of 100 Hz repetition rate operation for a E-O Q-switched Nd:YAG rod laser without water-cooling.
•100 Hz LD side-pumped Nd:YAG oscillator without water-cooling.•Distribution of pump light in the crystal and heat dissipation of the module.•Temperature, refractive index, stress and OPD distribution of the crystal.•Small size and compact structure.
We report an idler-resonant, continuous-wave (CW) seed injected, optical parametric oscillator (OPO) based on cadmium selenide (CdSe). The CdSe OPO was pumped by a 2.09 µm ns-pulsed laser and ...injection-seeded by a 2.58 µm CW laser. The idler-resonant oscillator was designed to maximize the optical-to-optical conversion efficiency and optimize the beam quality. The injected seed laser was designed to reduce the pump threshold. With this setup, the average idler output power of 802 mW was obtained corresponding to a pulse energy of 0.8 mJ at the wavelength of 11.01 µm and linewidth (FWHM) of 0.6 cm
−1
, optical-to-optical conversion efficiency of 4.4%, quantum conversion efficiency of 23.3%, beam quality of
M
2
x
= 1.23,
M
2
y
= 1.12, and pulse width of 21 ns. In addition, by turning the angle of the CdSe, wavelength tuning of 10.55-11.98 µm was achieved.
Pumped by a 100 W Q-switched Ho:YAG laser at 2090.7 nm with pulse repetition frequency of 10 kHz, four types of high-power long-wave infrared ZnGeP
2
(ZGP) subsequent optical parametric amplifier ...(OPA) based on optical parametric oscillator (OPO) with different types of phase matching (PM) of ZGP crystals were demonstrated. For the results of 8.2 µm output characteristics at the full incident pump power, Type-II PM ZGP OPO with Type-II PM ZGP OPA had the best
M
2
of 1.8 and lowest average output power of 9.2 W with the narrowest linewidth of 77 nm, while Type-I PM ZGP OPO with Type-I PM ZGP OPA had the worst
M
2
of 2.2 and the widest linewidth of 122 nm, and Type-II PM ZGP OPO with Type-I PM ZGP OPA had the highest average output power of 12.6 W, corresponding to overall optical conversion efficiency of 12.6% from Ho to long-wave infrared laser system.
A 2052.96 nm single-longitudinal-mode pulsed Ho:YVO
MOPA system was demonstrated for the first time. The pulsed Ho:YVO
MOPA system consisted of a unidirectional ring passively Q-switched oscillator ...and a single-pass amplifier. By inserting an isolator, a half-wave plate and a Cr
:ZnS plate into the ring Ho:YVO
oscillator cavity, the single-longitudinal-mode pulsed laser was achieved with an average output power of 1.02 W with pulse width of 910 ns and pulse repetition frequency (PRF) of 67 kHz. Using the residual (non-absorbed) pump power of the oscillator as pump, the single-pass pulsed Ho:YVO
amplifier obtained an average output power of 1.67 W. The total optical-to-optical efficiency of the pulsed Ho:YVO
MOPA system was 14.3%. Single-longitudinal-mode pulsed MOPA system based on isolator and Cr
:ZnS around 2 µm has not been reported yet to the best of our knowledge.
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