We report a high-peak-power, single-polarized master oscillator power amplification system employing polarizationmaintaining Yb-doped rod-type photonic crystal fiber. The MOPA system comprises of a Q-switched microchip laser generating ~630ps pulses at 8.6 kHz repetition-rate and two amplification stages employing double cladding fiber and rod-type PCF respectively. The MOPA system obtains narr...

In this paper an overview is given about laser surface modification processes, which are developed especially with the aim of hardness improvement for an enhanced fatigue and wear behaviour. The processes can be divided into such with and without filler material and in solid-state and melting processes. Actual work on shock hardening, transformation hardening, remelting, alloying and cladding i...

A novel method for fabricating microlenses on tapered single-mode fibers is shown to be able to control the lens spot size. The fiber cladding is first symmetrically tapered by etching it with an evaporating ammonium bifluoride solution. A hemispheric lens is then melted on the taper tip with a CO(2) laser. The lens can reduce the fiber mode radius to 40% of its original value. A theoretical ca...

A waveguide laser in an ytterbium-doped tantalum pentoxide film is reported. The waveguide is formed of a rib of sputtered tantalum pentoxide on top of oxidized silicon with an over-cladding of silica. Emission at a wavelength of 1025 nm was achieved with an absorbed pump power threshold and slope efficiency of ≈29  mW and 27%, respectively, for a cavity formed by a high reflector mirror and an...

We report performance characteristics of a thulium doped ZBLAN waveguide laser that supports the largest fundamental modes reported in a rare-earth doped planar waveguide laser (to the best of our knowledge). The high mode quality of waveguides up to 45 um diameter (~1075 μm(2) mode-field area) is validated by a measured beam quality of M(2)~1.1 ± 0.1. Benefits of these large mode-areas are dem...

The resonant pumping of holmium fibre lasers provides a fibre laser platform capable of addressing a wide range of applications that benefit from operation at wavelengths beyond 2.1 μm. This architecture can provide laser devices that promise high efficiency sources in the 2.1 μm spectral region with excellent beam quality and power scalability. This paper presents our recent results of resonan...

Laser cladding coating with wolfram carbide (WC) as enhanced particles can improve the performance of nickel-based materials. However, there still exists several problems, such serious element segregation and unequal distribution reinforcement phase. In order to mechanical properties further, IN718/WC coatings were prepared by ultrasonic vibration-assisted laser cladding. The effects vibration ...