Publications by authors named "Renjiang Zhu"

This paper presents a high power widely tunable frequency-doubled semiconductor disk laser emitting at 490 nm wavelength. The laser utilizes a specially designed gain chip with widened gain spectrum at the center wavelength of 980 nm, along with an anti-resonant microcavity, to extend the tuning range of the wavelength. A type-I phase-matched 5 mm length LBO crystal is used as the nonlinear crystal, and a fused quartz birefringent filter (BRF) is introduced to polarize the fundamental emission and narrow the linewidth of the laser.

View Article and Find Full Text PDF

Reducing the repetition rate is one of the effective ways to increase the peak-power of the mode-locked pulses. However, for a vertical-external-cavity surface-emitting laser (VECSEL), the carrier lifetime in the nanosecond regime limits the further reduction of the pulse repetition rate, or in other words, limits the average output power of the mode-locked laser at low repetition rates, and ultimately restricts the peak-power of the pulses. This work uses a specially designed saturable Bragg reflector to start the mode-locking, and both low repetition rate and high average power are achieved simultaneously in a passively mode-locked VECSEL.

View Article and Find Full Text PDF

Understanding the mechanism of mode-locking in a laser with high-order transverse mode is important for achieving an ultrashort pulses train under more complicated conditions. So far, mode-locking with high-order transverse mode has not been reported in other lasers except the multimode fiber laser. This paper demonstrates robust mode-locking with high-order transverse mode in a Kerr-lens mode-locked vertical-external-cavity surface-emitting laser for the first time, to the best of our knowledge.

View Article and Find Full Text PDF

Advanced light sources in the blue-green band are crucial for underwater wireless optical communication (UWOC) systems. Vertical-external-cavity surface-emitting lasers (VECSELs) can produce high output power and good beam quality, making them suitable for UWOC. This paper presents a 108 m distance UWOC based on a 100 mW 490 nm blue VECSEL and an acousto-optic modulator (AOM).

View Article and Find Full Text PDF

Semiconductor disk lasers can produce high output power and good beam quality simultaneously. The high intracavity circulating power of about hundreds of watts, along with the flexibility of tailorable emitting wavelengths, make it an attractive light source for obtaining ultraviolet (UV) radiation from near-infrared lasers through nonlinear frequency conversion. This work reports a frequency tripled 327 nm semiconductor disk laser with record output power and wavelength tuning range by using a type-I phase-matched LiBO (LBO) crystal and a type-I phase-matched β-BaBO (BBO) crystal as the frequency-doubling and -tripling crystals respectively.

View Article and Find Full Text PDF

We report a widely tunable optically pumped vertical-external-cavity surface-emitting laser. The multiple quantum wells in the active region of the gain chip are generally designed to form the resonant periodic gain structure, and three different methods are used to tune the oscillating wavelength. The maximum wavelength coverage of 45 nm is obtained when a 2 mm thickness birefringent filter is introduced in a straight-line cavity, while the tuning range of 8 nm is performed by employing a 0.

View Article and Find Full Text PDF

Dual-wavelength lasers with separation from several nanometers to tens of nanometers at 1 µm waveband are attractive light sources for terahertz generation. This work reports a compact dual-wavelength vertical-external-cavity surface-emitting laser with simple elements. The gain chip is regularly designed and epitaxially grown, and the laser cavity is the most common straight line cavity.

View Article and Find Full Text PDF