ABSTRACT
We report on the experimental results of a diode-pumped, intracavity-doubled cw Nd:YAG laser, pumped by a 10-W fiber-coupled semiconductor laser at 808 nm and emitting as much as 600 mW in a stable single longitudinal mode and TEM(00) spatial mode. We discuss the main issues of the resonator design and the optimization of the intracavity second harmonic conversion by interpreting our results using simple models. Improvements for the current project are also discussed.
ABSTRACT
A quasi-cw diode-pumped Nd:YAG laser, mode locked by a nonlinear mirror and stabilized by an acousto-optic modulator, has been developed that generates 31-ps, 23-microJ pulses. Employing this source with a periodically poled lithium niobate crystal in a traveling-wave geometry, we obtained extracavity frequency conversion with pump depletion of as much as 62% in the near infrared (1.46- 1.56 microm) with a pulse spectral width of 1.5nm and a beam quality M(2)=1.7.
ABSTRACT
A diode-pumped Nd(3+):YVO(4) laser passively mode locked by a nonlinear mirror based on second-harmonic generation has been developed. Pumping with a fiber-coupled 10-W diode array, we generated nearly diffraction limited, linearly polarized 11-ps pulses at 1064nm, with average power of 2.7 W at a 150-MHz repetition rate. Pulses as short as 7.9 ps were measured with reduced output power (1.35 W) by optimal focusing in the nonlinear crystal.
ABSTRACT
We present a novel interpretation of Kerr lens mode locking based on the Z-scan operating principle and derive a few practical criteria for application to mode-locked solid-state laser systems.
ABSTRACT
Time-resolved M(2) numerical computation and experimental measurements of nanosecond pulses from a Q-switched variable-reflectivity-mirror Nd:YAG laser are presented for the first time to our knowledge. The beam quality parameter is seen to vary approximately from 1 at the beginning to 2 at the end of a high-energy pulse, with a value of 1.35 at the peak of the pulse, which also corresponds to the M(2) obtained from the time-averaged detection of the pulse profile.
ABSTRACT
A novel method for measuring the beam quality of short, powerful laser pulses is presented. The method is based on the Z-scan technique used to investigate the nonlinear susceptibilities of optical materials. It is shown that both two-photon absorption and nonlinear refraction of a nonlinear sample can be used to obtain information about the spatial quality of the pulses.
ABSTRACT
Stationary ultrashort light pulses of 10-psec duration and with an energy of 10 microJ per pulse were obtained from an active-passive mode-locked Nd:YAG laser by using a two-photon absorption limiter (GaAs) inserted into the resonator. The stability of energy in the steady-state part of the pulse train, containing approximately 90 pulses, is better than +/-1.5%. The dynamics of the pulse-shortening mechanism are described, and it is shown that maximum pulse compression is reached after only approximately 10 round trips.
ABSTRACT
A novel cavity design based on a confocal negative branch unstable resonator configuration is presented. A proper choice for the size of the field limiting aperture, set at the common focal plane of the mirrors, results in removal of the hot spot inside the cavity and in the smoothing of the spatial profile of the oscillating mode. Application of this scheme to a pulsed Nd:YAG oscillator is thoroughly characterized in a variety of operational modes (fixed-Q, Q-switching, mode-locking). The main results are a high efficiency of energy extraction and excellent phase and amplitude profiles of the output beam, which shows real transform-limited performances.
ABSTRACT
A mode-locked Nd:YAG oscillator is described that operates at 1.052 microm. It is shown that a birefringent filter efficiently discriminates and selects each one of the fundamental Nd:YAG transitions.
