Diode-pumped passively mode-locked Nd:YVO4 laser at 914 nm

We demonstrate, for the first time, to our knowledge, a diode-pumped passively mode-locked Nd:YVO4 laser, operating on the 4F(3/2)-4I(9/2) transition of the neodymium ion at 914 nm. We obtained 8.8 ps pulses at approximately 914 nm at a repetition rate of 94 MHz, and an averaged output power of 87 mW by using a semiconductor saturable absorber mirror.     

Robust diode-end-pumped Nd:GdVO4 laser passively mode-locked with saturable output coupler

Passively mode-locked diode-pumped solid-state (DPSS) Nd:GdVO₄ laser by using a saturable output coupler (SOC) in stable two-mirror linear cavity design is demonstrated. The laser was pumped by low-power single laser diode without any active cooling and external optics. Robust CW mode-locked operation was obtained with a repetition of 150–250 MHz, the pulsewidth was 12 ps, the lowest threshold for CW mode-locked was 185 mW. The optimal condition is found when the laser provides the set of characteristics: low CW mode-locking threshold (～260 mW), compact size (total cavity length 60 cm), good efficiency (～20%), and very stable output. At the output power of 270 mW an average power fluctuations within ±2% for long-term operation was obtained.     

High-pulse-energy passively mode-locked Nd:YVO4 laser without spatial hole burning effect

We report on a high-pulse-energy 888 nm diode-pumped passively mode-locked TEM₀₀ Nd:YVO₄ oscillator without spatial hole burning (SHB) effect in active medium. At a pump power of 40 W, the oscillator produced pulse energy up to 270 nJ at a repetition rate of 50 MHz, corresponding to average power of 13.5W with 34% optical-to-optical efficiency. To the best of our knowledge, it is the highest pulse energy obtained at the same pump power. The pulse duration produced varied from 16 to 59 ps. By varying the pump power, we observed a pulse duration ranging from 52 to 59 ps while the time-bandwidth product remained 0.88, and the factors that affect the pulse duration were also discussed. Meanwhile, a novel method of adjusting output coupling (OC) was introduced, which can simplify the structure of laser.     

Wall paper single-walled carbon nanotubes absorber for passively mode-locked Nd: GdVO4 laser

A novel and low-cost wall paper single-walled carbon nanotubes (SWCNTs) absorber was fabricated by high viscosity of polyvinyl alcohol (PVA) aqueous solution and vertical evaporation technique. Sandwich structure wall paper SWCNT (SSWA-SWCNT) absorber was constructed by a piece of wall paper SWCNT absorber, a piece of round quartz and an output coupler mirror. We exploited it to realize mode locking operation in a diode-pumped Nd: GdVO₄ laser. A pulse duration of 9.6 ps was produced with an average power of 870 mW. The stable mode locking operation was obtained when the average power is less than 300 mW.     

Diode-end-pumped passively mode-locked high-power Nd:YVO4 laser with a relaxed saturable Bragg reflector

We demonstrate a high-power passively mode-locked Nd:YVO (4) laser that uses a saturable Bragg reflector (SBR) with strain relaxation. 23.5 W of average power with ~21.5-ps cw mode-locked pulse trains was generated at a 50-W pump power. Experimental results show that appropriate strain relaxation in the SBR makes the mode-locking operation less sensitive to temperature variation.     

Optimization of diode-pumped passively Q-switched mode-locked c-cut Nd:GdVO4 laser with a GaAs saturable absorber

By considering the single-photon absorption (SPA) and two-photon absorption (TPA) processes in the GaAs saturable absorber, the coupled rate equations for a diode-pumped passively Q-switched and mode-locked (QML) laser with GaAs coupler under Gaussian approximation are given. The key parameters of an optimally coupled passively QML laser can be obtained by numerically solving these equations. These key parameters include the parameters of the gain medium, the saturable absorber and the resonator, which can maximize the pulse energy of singly Q-switched envelope. Sample calculations for a diode-pumped passively Q-switched mode-locked c-cut Nd:GdVO₄ laser with a GaAs saturable absorber are presented to demonstrate the optimal method applicable.     

5.3-W Nd:YVO4 passively mode-locked laser by a novel semiconductor saturable absorber mirror

We report a diode end-pumped continuous wave (CW) passively mode-locked Nd:YVO4 laser with a homemade semiconductor saturable absorber mirror (SESAM). The maximum average output power is 5.3 W at the incident pump power of 17 W, which corresponds to an optical-optical conversion efficiency of 31.2% and slope efficiency of 34.7%. The corresponding optical spectrum has a 0.2-nm full width at half maximum (FWHM), and the pulse repetition rate is 83 MHz.     

Diode-pumped, Cr:YAG passively Q-switched and mode-locked Nd:YVO_4/KTP green laser

The phenomena of simultaneous Q-switching and mode-locking in a diode-pumped Nd:YVO4/Cr:YAG/ KTP green laser are reported and discussed in this paper. With 5.3-W pump power, by using a nearly hemispherical cavity (the cavity length is only 97 mm), the results of modulation depth of 70% and the period of 0.6 ns are obtained, the output power and the repetitive frequency of Q-switched pulse are 90 mW and 12 kHz, respectively.     

Passively mode-locked 914-nm Nd:YVO4 laser

We demonstrate what is to our knowledge the first mode-locked Nd:YVO4 laser operating on the 4F3/2-4I9/2 transition at 914 nm. Using a semiconductor saturable-absorber mirror for passive mode locking, we have obtained 3-ps pulses at a repetition rate of 233.8 MHz. The laser is based on a standard delta cavity and is pumped by a Ti:sapphire laser. We obtained an average output power of 42 mW through one mirror and an accumulated output power of approximately 150 mW (through all cavity mirrors) at a pump power of 1.4 W.     

Diode-pumped passively mode-locked Nd:YVO4 laser at 1342 nm with periodically poled LiNbO3

In this Letter, we demonstrate a nonlinear-mirror (NLM) mode-locked diode-pumped solid-state Nd:YVO4 laser operating at 1342?nm, in which the NLM comprises a periodically poled LiNbO3 crystal and a dichroic mirror. The self-starting threshold for cw mode locking is 1.5?W, which is significantly lower than that of saturable absorber mode locking. An average power of 1.52?W at 1342?nm is obtained under diode pump power of 10?W at 808?nm, with the slope efficiency being up to 16.8%. The pulse width and the repetition rate of the mode-locked laser output are about 9.5?ps and 101?MHz, respectively.     

Fluorescence lifetime imaging with a low-repetition-rate passively mode-locked diode-pumped Nd:YVO4 oscillator

We report a wide-field fluorescence lifetime imaging microscope based on a low-repetition-rate (3.7-MHz) passively mode-locked diode-pumped laser source. This inexpensive and compact laser source operating in the visible and UV range can excite a wide range of fluorophores of biological interest. We demonstrate that the power of this laser source is highly sufficient for studying biological systems with low quantum yields (autofluorescence of tissues and stained living cells). The maximum measurable lifetime is also strongly increased with this laser source, as fluorescence intensity measurement can occur 250 ns after the excitation pulse.     

InAs/GaAs quantum-dot saturable absorber for a diode-pumped passively mode-locked Nd:YVO4 laser at 1342 nm

We report that InAs/GaAs quantum dots were developed to be saturable absorbers as well as output couplers in diode-pumped passively mode-locked Nd:YVO4 lasers at 1342 nm. With an incident pump power of 12.6 W, an average output power of 0.85 W with a mode-locked pulse width of 26 ps at a repetition rate of 152 MHz was obtained.     

Diode-pumped passively mode-locked Nd:CLNGG laser

Passive mode-locking of a diode-pumped Nd:CLNGG laser was demonstrated for the first time to our knowledge. The laser operated at a central wavelength of 1061.2 nm with a maximum average output power of 101 mW. The mode-locked pulses have pulse duration of 2.0 ps, a spectral bandwidth of 1.2 nm and a repetition rate of 88.4 MHz. The mode locking of the laser was enabled by a semiconductor saturable absorber mirror (SESAM).     

Q-switched mode-locked diode-pumped Nd:YVO4 laser with a saturable Bragg reflector

We demonstrated a diode-pumped passively Q-switched mode-locked Nd:YVO4 laser by using a relaxed saturable Bragg reflector (SBR). Stable mode-locked pulse train with the repetition rate of ～230 MHz was achieved and the pulse train was modulated by the Q-switched envelope with the repetition rate of ～150 kHz. The maximum output of 4 W was obtained under the pump power of 13.5 W. The optical-to-optical efficiency was 30%. We also discussed the transition of each process having emerged.     

cw dual-wavelength operation of a diode-end-pumped Nd:YVO4 laser

A dual-wavelength continuous wave (cw) diode-end-pumped Nd:YVO₄ laser that generates simultaneous laser action at the wavelengths 1064 nm and 1342 nm is demonstrated. The optimum oscillation condition for the simultaneous dual-wavelength operation in a diode-end-pumped solid-state laser has been derived. The relationship between the laser cavity and the output stability is also studied. Experimental results show that the stability of the output power at the two wavelengths could be enhanced by use of a three-mirror cavity. Received: 26 August 1999 / Revised version: 11 October 1999 / Published online: 23 February 2000     

Diode-end-pumped passively mode-locked Nd:LuVO4 laser with a semiconductor saturable-absorber mirror

A diode pumped passively mode-locked Nd:LuVO₄ laser with a semiconductor saturable-absorber mirror (SESAM) is demonstrated. The mode-locked pulses have a pulse duration of about 8.8 ps and a repetition rate of 157 MHz. Under an absorbed pump power of 12 W a maximum output power of 3.71 W is obtained, which gives an optical conversion efficiency of 31%. Our results show that Nd:LuVO₄ is a promising gain medium for the high power mode-locked solid-state lasers.     

532-nm picosecond pulse generated in a passively mode-locked Nd:YVO_4 laser

A diode-pumped continuous-wave （CW） mode-locked Nd：YVO4/KTP green laser with semiconductor saturable absorber mirror （SESAM） is demonstrated. The maximum output power of CW mode-locked green laser is obtained to be 552 mW at the incident pump power of 7.25 W, corresponding to an opticai-optical conversion efficiency of about 7.6%. The 532-nm CW mode-locked pulse duration is estimated to be about 8.4 ps with the repetition rate of 87 MHz.     

Efficient subnanosecond diode-pumped passively Q-switched Nd:YVO4 self-stimulated Raman laser

Generation of efficient subnanosecond self-stimulated Raman pulses by a diode-pumped passively Q-switched Nd:YVO4/Cr4+:YAG laser is demonstrated. Experimental results reveal that self-frequency Raman conversion can be achieved with a c-cut Nd:YVO4 crystal in a nearly hemispherical cavity. At 2.0 W of incident pump power, the self-stimulated Raman laser produces stable 710-ps pulses at a Stokes wavelength of 1178.6 nm with 7.2 microJ of pulse energy at a 17-kHz repetition rate.     

Diode-pumped passively Q-switched Nd:YVO4 laser with GaAs saturable absorber

The intracavity photon density is assumed to be of Gaussian spatial distributions and its longitudinal variation is also considered in the rate equations for a laser diode(LD)end-pumped passively Q-switched Nd:YVO4 laser with GaAs saturable absorber.These space-dependent rate equations are solved numerically.The dependences of pulse width,pulse repetition rate,single-pulse energy,and peak power on incident pump power are obtained.In the experiment,the LD end-pumped passively Q-switched Nd:YVO4 laser with GaAs saturable absorber is realized and the experimental results are consistent with the numerical solutions.