Compact femtosecond laser operation of Yb:Gd(2)SiO(5) (Yb:GSO) crystal was demonstrated under high-brightness diode-end-pumping. A semiconductor saturable absorption mirror was used to start passive mode-locking. Stable mode-locking could be realized near the emission bands around 1031, 1048, and 1088 nm, respectively. The mode-locked Yb:GSO laser could be tuned from one stable mode-locking band to another with adjustable pulse durations in the range 1~100 ps by slightly aligning laser cavity to allow laser oscillations at different central wavelengths. A pair of SF10 prisms was inserted into the laser cavity to compensate for the group velocity dispersion. The mode-locked pulses centered at 1031 nm were compressed to 343 fs under a typical operation situation with a maximum output power of 396 mW.

We report an efficient Q-switched laser action based on a semiconductor saturable absorber mirrors (SESAMs) as passively Q-switched laser starter and a Yb:LYSO alloyed crystal as gain material pumped directly by 974 nm In GaAs laser diodes. The output pulse duration is measured to be about 7μs, while the average power and the repetition rate of the pulse chain are about 0.92 W and 6.2kHz, respectively, under 12.5 W absorbed pumping power. The Q-switched mode-locked pulse train is also observed in this setup. The laser performance shows that Yb:LYSO is a promising laser gain medium for laser-diode pumped compact solid-state lasers.

Yb : Gd 2 Si O 5 (Yb:GSO) exhibits a large fundamental manifold splitting. Its long-wavelength emission band around 1088nm, which has the largest emission cross section, encounters the lowest reabsorption losses caused by thermal population of the terminal laser level. As a result, low-threshold and tunable continuous-wave Yb:GSO lasers were demonstrated. A slope efficiency up to 86% and a pumping threshold as low as 127mW were achieved for a continuous-wave Yb:GSO laser at 1092.5nm under the pump of a high-brightness laser diode. A continuous tunability between 1000 and 1120nm was realized with an SF14 prism as the intracavity tuning element.

All-optical synchronization of 1064 nm pulses with femtosecond laser pulses at 794 nm is realized on the basis of continuous-wave laser seeded non-collinear optical parametric amplification, by using a CW laser at 632.8 nm as the seeded signal and intense frequency-doubled Ti:sapphire femtosecond laser at 396 nm as the pumping source. The generated background-free idler pulses at 1064 nm can be used as an accurately synchronized pump seed for the optical parametric amplification of ultra-broadband chirped Ti:sapphire laser pulses.

A high-performance microcavity sensor with a port connected with a waveguide directly is investigated numerically. With input light and output light transmitting in the same waveguide, we propose a robust coupling mechanism. For a circular microcavity with a diameter of 20μm and a refractive index of 1.45, our numerical results show that the coupled modes are excited and more than 5×104 Q-factor is calculated from the transmission spectrum. Dramatically, the spectrum shows a fano-shape resonance at specific wavelength which is useful for high-precision optical sensing on the order of 10-5.