A. I. Ferguson

Self-mode locking of a diode-pumped Nd:YLF laser.

We report on the self-mode locking of a diode-laser-pumped Nd:YLF laser. Pulses of 6-ps duration have been obtained by using only a glass rod placed at an intracavity focus and an aperturing slit near the output coupler to achieve pulse shaping. The mode-locking mechanism is believed to be that of self-focusing (Kerr lens mode locking) owing to the optical Kerr effect in the glass rod. The pulses are approximately bandwidth limited, and the process can be self-started by a mechanical perturbation to the system.

Additive-pulse mode locking of a diode-pumped Nd:YLF laser

We investigate the passive self-starting technique of additive-pulse mode locking of a diode-laser-pumped Nd:YLF laser. Pulses of 1.5-psec duration at a repetition rate of 123 MHz have been obtained, using only a single-mode optical fiber in an external feedback cavity to achieve pulse formation. The sech(2) pulses are approximately transform limited and to our knowledge the shortest that have been produced by a Nd:YLF laser. The laser was pumped by two 1-W laser-diode arrays and had usable output power of 20 mW, corresponding to a peak power of 108 W.

Application of a femtosecond self-sustaining mode-locked Ti:sapphire laser to the field of laser scanning confocal microscopy

Developments in ultrafast Ti:sapphire laser technology can be applied in the investigation of nonlinear optical processes. We describe the application of a self-sustaining femtosecond Ti:sapphire laser as an illumination source in the field of confocal laser scanning fluorescence microscopy (LSM). We present spectra for various fluorescent stains under two-photon excitation and present LSM images of stained samples under mode-locked illumination. The potential for such a system as a non-destructive technique for studying live cells in biomedical research is discussed.

High-average-power (>20-W) Nd:YVO 4 lasers mode locked by strain-compensated saturable Bragg reflectors

Strain-compensated double InGaAs quantum-well saturable Bragg reflectors (SBR’s) with high damage thresholds have been developed for use as mode-locking elements in high-average-power neodymium lasers. Nd:YVO4 lasers have been developed with these new SBR’s, which produce transform-limited pulses of 21-ps duration at 90 MHz and an average power of 20 W in a diffraction-limited output beam. The peak pulse power at an output power of 20 W was 10.6 kW. A comparison of the operating parameters of strained single and strain-compensated double-well SBR’s indicates that the damage threshold increased by a factor of at least 2–3. Long cavity laser variants were investigated to assess the limitations of further power scaling. At a repetition frequency of 36-MHz stable mode-locked pulses with peak pulse powers of 24.4 kW and pulse energies of 0.6 µJ could be generated.

Two-photon spectroscopy of laser-cooled Rb using a mode-locked laser

Abstract Using laser cooled samples of 85Rb and 87Rb in a magneto-optical trap, high resolution spectroscopy of the two-photon transitions 5 S 1 2 −5 D 3 2 , 5 S 1 2 −5 D 5 2 and 5 S 1 2 −7 S 1 2 have been investigated using the output from a mode-locked titanium sapphire laser. The hyperfine constants for the 7S terms of both isotopes have been measured with improved accuracy.

Actively mode-locked Ti:sapphire laser producing transform-limited pulses of 150-fs duration

We report on the generation of transform-limited pulses of 150-fs duration from an actively mode-locked Ti:sapphire laser. The laser produced subpicosecond pulses over the range 780-860 nm, with a maximum average output power of 600 mW. The output spot was in the form of a near-TEM(00) spot and demonstrated longterm pulse stability.

OPTICAL COMB GENERATOR AS AN EFFICIENT SHORT-PULSE SOURCE

We demonstrate a novel technique for converting a continuous-wave laser beam into a stable train of short pulses with a high repetition rate. The system, which is generally applicable, is based on a purely passive coupled-cavity optical frequency comb generator, which ensures a high overall efficiency. The repetition rate of the device is determined by the drive frequency of an electro-optic modulator and the pulse width by the rf power applied to the modulator. We have observed pulses down to 3.3 ps long at a 5.34-GHz repetition rate and an overall efficiency of 11%. The experimental results for pulse shape and width show excellent quantitative agreement with the results of a simple model.

Tunable narrow linewidth ultra-violet light generation by frequency doubling of a ring Ti:sapphire laser using lithium tri-borate in an external enhancement cavity

Abstract In this paper the generation of tunable narrow linewidth ultra-violet light by frequency doubling of a ring Ti:sapphire laser using lithium tri-borate in an external enhancement cavity is reported. Using a small frame argon-ion pump laser (6 W), a single frequency output of 60 mW at 380 nm and more than 10 mW between 360 and 400 nm has been generated. the Ti:sapphire laser was locked to an external reference cavity and had a residual linewidth of less than 50 kHz. The uv frequency could be scanned continuously over 35 GHz.

Self-mode-locked diode-pumped Cr:LiSAF laser

We describe an all-solid-state tunable self-mode-locked Cr:LiSAF laser that is pumped with a single 250-mW laser diode and produces almost-bandwidth-limited pulses of 97-fs duration. The self-mode locking is initiated by a regeneratively driven acousto-optic modulator, and the cavity incorporates a hard aperture in the form of an adjustable slit. The design considerations for low-threshold self-mode-locked diode-pumped lasers are outlined.

Self-mode-locked diode-pumped Cr:LiSAF laser producing 34-fs pulses at 42-mW average power

We describe a self-mode-locked diode-pumped Cr:LiSAF laser producing almost-bandwidth-limited tunable pulses of 34-fs duration at an average power of 42 mW. We discuss the capacity of this laser to produce even-shorter pulses and how their quality may be improved by reduction of pulse-duration limiting effects.