Growth and application of [01·4] LiNbO3

We have successfully grown large, high quality LiNbO₃ boules in the [0.1·4] direction which lies in the yz plane 38° to the z. Following annealing and poling the material is strain free, striation free and of high optical quality. It has been used to fabricate an electro-optic switch, for second harmonic generation and tunable parametric generation over the 1.4 μm to 4.4 μm spectral range.     

Bidirectional, synchronously pumped, ring optical parametric oscillator

We report the operation of a bidirectional femtosecond pulsed ring optical parametric oscillator based on periodically poled lithium niobate, pumped alternately with nonsimultaneous pulses from a Ti:sapphire mode-locked laser. A beat note between the two counterpropagating beams attests to a gyro response without dead band. The sensitivity of the device to differential phase changes is demonstrated by measurement of the nonlinear index of lithium niobate.     

Yb:YAG and Nd:YAG edge-pumped slab lasers

Experimental demonstrations of two edge-pumped zigzag slab lasers are presented. The Nd:YAG slab laser generated 127 W of multimode output power with 300W of pump power. Preliminary results with a Yb:YAG slab produced 46 W of output power with 315W of pump power. The edge-pumped slab design permits symmetric conduction cooling and efficient pump absorption and accepts large-numerical-aperture pump sources.     

Diode-pumped moving-disc laser: a new configuration for high average power generation

In this paper we report a new geometry for diode laser pumping. We show that an efficient moving-disc laser can be designed which can operate at 20 kW of average power with existing diode laser technology.     

Linearly polarized, 3.35 W narrow-linewidth, 1150 nm fiber master oscillator power amplifier for frequency doubling to the yellow

A high-power linearly polarized Yb-doped silica fiber master oscillator power amplifier at 1150 nm is reported. It produced 3.35 W cw and 2.33 W of average power in 1 micros pulses at a 100 kHz repetition rate, both with 8 pm linewidth. This is the first report, to the best of our knowledge, of a high-power Yb-doped fiber amplifier at a wavelength longer than 1135 nm. The pulsed output was frequency doubled in a bulk periodically poled near-stoichiometric LiTaO(3) chip to generate 976 mW of average power at 575 nm with an overall system optical-to-optical efficiency of 9.8% with respect to launched pump power.     

A 200 mJ unstable resonator Nd:YAG oscillator

We have designed and operated a positive branch 6.3 mm diameter rod Nd:YAG unstable resonator oscillator with a 12 nsec, 200 mJ Q-switched output at 10 Hz repetition rate. When followed by a single 9 mm diameter Nd:YAG amplifier output energies up to 750 mJ were obtained with a divergence less than 0.5 mrad.     

A guided wave monolithic resonator ruby fiber laser

Single crystal ruby fibers, cooled with liquid nitrogen, have been operated as end pumped lasers. The fiber laser is a guided wave device with a length of 15 mm and a mean diameter of 60 μm. The laser resonator structure is monolithic, consisting of an aluminium mirror coated on one fiber end face and an uncoated opposite end face serving as an output coupler. Using an argon ion laser pump source, cw output powers of several mW were obtained.     

Remote air pollution measurement

The availability of high energy tunable laser sources has extended the possibilities for remote air pollution measurement. This paper presents a discussion and comparison of the Raman method, the resonance and fluorescence backscatter method, long path absorption methods and the differential absorption method. A comparison of the above remote detection methods shows that the absorption methods offer the most sensitivity at the least required transmitted energy. Topographical absorption provides the advantage of a single ended measurement, and differential absorption offers the additional advantage of a fully depth resolved absorption measurement. Recent experimental results confirming the range and sensitivity of the methods are presented. Future widespread use of remote pollution monitoring will probably be limited to the infra-red to interact with molecular spectral bands and to meet eye safety requirements.     

Electronic linewidth narrowing method for single axial mode operation of Q-switched Nd: YAG lasers

Electronic control of the Q-switch is used to obtain single axial mode output from an unstable resonator Nd: YAG oscillator. Controlled opening of the Q-switch following prespiking pulses provides over 10 MW of peak power in a single axial mode without significant output power reduction.