Huy-Zu Cheng

Passively Q-switched quasi-three-level laser and its intracavity frequency doubling

A passively Q-switched quasi-three-level Nd:YAG laser is intracavity frequency doubled to generate a blue laser. The 473-nm blue laser has a peak power of 37 W and a pulse width of 23 ns at a pumping power of 1.6 W. To model this laser numerically, we developed rate equations by taking into consideration both the quasi-three-level nature of the gain medium and the four-level nature of the saturable absorber. Good agreement was achieved between experimental and simulated results for both the fundamental and the second-harmonic output. The reabsorption loss of the gain medium is estimated under pulsed operation.

Multi-reentrant nonplanar ring laser cavity

A multi-reentrant nonplanar ring laser cavity configuration is presented. Two identical spherical mirrors were used to construct the laser cavity. The exact reentrant condition of the ring cavity is derived and the stability of the laser cavity is analyzed. Although slight astigmatism can arise from the intracavity elements, the cavity itself is astigmatism-free. Linear output polarization is readily achieved. A 3-atm.% Nd doped YAG with 1-mm thickness was used as the gain medium to reduce beam distortion, and the gain medium also served as a Faraday rotator to control the laser beam propagation direction. The laser cavity length is short, whereas the laser beam round-trip length can be long. A factor of 13-times enlargement in round-trip length is demonstrated.

Reentrant two-mirror ring resonator for generation of a single-frequency green laser

A nonplanar, reentrant two-spherical-mirror ring cavity is demonstrated. It is compact and free of astigmatism. Unidirectional operation is achieved by use of reciprocal and nonreciprocal polarization rotators to differentiate round-trip loss. A single-frequency green laser is generated by intracavity frequency doubling. Amplitude noise as low as 0.25% is achieved.

A Passively Q-Switched Laser Constructed by a Two-Mirror Reentrant Ring Cavity

A passively Q-switched laser is demonstrated by a two-mirror reentrant and unidirectional ring cavity. Due to the cavity configuration, the pulse-to-pulse timing jitter is effectively reduced to less than 3% over 40,000 shots. As indicated in our simulation on photon dynamics in the cavity, spontaneous noise from the gain medium is the major cause of large timing jitter in passively Q-switched lasers, and it is eliminated in this laser.

Passively Q-switched three-level laser and its intracavity frequency-doubling

By combining the passive Q-switching and the intracavity frequency-doubling techniques, a diode-pumped solid-state blue laser is demonstrated. The 473-nm blue laser has a peak power of 114 watts and a pulse width of 10.6 ns with a pumping power of 3 watts.

Timing-jitter reduction of passively Q-switched laser by a reentrant 2-mirror ring cavity

Summary form only given.Passive Q-switching has shown to be a compact and efficient expedient to generate high-peak-power laser pulses. We use a novel reentrant 2-mirror ring cavity for the passive Q-switching system. The ring cavity effectively reduces the spontaneous noise influence upon the saturable absorber. Especially, under uni-directional operation the timing jitter is largely reduced to 3%.

Diode-laser pumped high-power and actively mode-locked Nd:YLF laser with fast switching

In an actively mode-locked laser, self-phase modulation can make pulse shorter at the expanse of causing instability at high pumping power. Using fast switching on the acousto-optic modulator, we can generate an actively mode-locked pulse train with shorter pulse width and higher average power than that driven by a sinusoidal signal. A 9-ps pulse train was generated in a mode-locked laser with an average power of 600 mW whose power level, to our knowledge, is the highest for diode-pumped and mode-locked Nd:YLF lasers.

Reduction of thermally-induced polarization rotation in a nonplanar ring laser cavity

The polarization evolution in a nonplanar and reentrant ring cavity is characterized by measuring the thermal birefringence and analyzing the polarization rotation due to cavity configuration. The thermally induced polarization rotation is significantly reduced in this nonplanar ring cavity compared to linear cavity.

Reentrant two-mirror laser ring cavity for the generation of single frequency green laser

A non-planar and reentrant two-mirror ring cavity is proposed. It is compact and astigmatism free. With unidirectional control, single frequency green laser is demonstrated.

Compact solid-state green laser and its application in microwave generation

Compact solid-state green lasers are developed for microwave generation. Two approaches are described in this paper. One uses a laser operated at two-mode oscillation state; the other uses compact ring-cavity lasers. The properties of these lasers are analyzed. The two-mode oscillation is a result of gain saturation and mode competition in the gain medium. The compact ring-cavity laser is realized by a novel 2-mirror cavity with three-dimensional figure-8 beam path.