Educação matemática pela arte
Gusmão, Lucimar Donizete
2013-08-28
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283 records were found.
Fabricating low loss planar waveguides in crystal laser hosts can lead to very large inversion densities for relatively low pump powers due to the confinement of light to small dimensions over longer lengths than normally allowed by diffraction. Thus very high gain per unit pump power amplifiers and very low threshold lasers are made possible. Planar waveguides also allow easy access to the guided wave which can be useful for integrated functions (gratings, modulators etc) and good heat removal in high power devices. Here two methods of producing planar waveguide lasers in a variety of interesting host crystals are discussed.
We present a diode- pumped, double-clad Yb:YAG waveguide laser that maintains an integrated section of Cr4+:YAG saturable absorber for passive Q switching. Using two 4-W polarization-coupled, broad-stripe diode-pumped lasers, we obtained 30μJ pulses of 16-ns duration at repetition rates of as much as 77 kHz. The slope efficiency was ~50% with respect to absorbed pump power, with a maximum output average power of 2.3 W and a peak power of ~18 kW. The output beam was single lobed, with M2 values as great as 1.5 x 1.3 . We also demonstrate a passively Q-switched Nd:YAG waveguide laser of similar design, operating at 1064 μm and 946 nm.
Lasers based on planar optical waveguides have recently generated interest for use as high-average-power sources, due to a combination of attractive features including high optical gain, good thermal-power handling and compatibility with the geometry of high-power diode pump sources [1,2]. However, high-power diode pumping of monolithic plane-plane waveguide cavities generally leads to multi-mode output. One possible route to controlling the spatial output of such devices is through the use of tapered waveguides [3]. For devices of a few centimetres in length, adiabatic expansion can be achieved up to widths of a few hundred microns. This leads to structures compatible with end-pumping by broad-stripe diodes or, for higher power, side-pumping by diode bars. The latter route requires a very strong absorption of the diode emission, as th...
The thermal diffusion of Nd3+ and Gd3+ ions in YVO4 is characterised in terms of diffusion rates, spectroscopy, and index change in order to fabricate optical waveguides suitable for laser operation.
The thermal diffusion of Nd3+ and Gd3+ ions in YVO4 is characterised in terms of diffusion rates, spectroscopy, and index change in order to fabricate optical waveguides suitable for laser operation.
The thermal diffusion of Nd3+ and Gd3+ ions in YVO4 is characterised, finding diffusion rates of 7x10−19 and 44x10−19 m2s−1 respectively at 1400°C, and activation energies of 5.3x10−19 and 2.9x10−19 J respectively, for diffusion along the c-axis. The fluorescence properties of the Nd3+-diffused YVO4 agree well with those of bulk doped materials. The formation of a planar optical waveguide was also observed for one of the Nd3+-diffused samples. This characterisation is a significant first step towards fabrication of waveguide lasers and amplifiers in this important laser material.
Lasers based on planar optical waveguides have recently generated interest for use as high-average-power sources, due to a combination of attractive features including high optical gain, good thermal-power handling and compatibility with the geometry of high-power diode pump sources [1,2]. However, high-power diode pumping of monolithic plane-plane waveguide cavities generally leads to multi-mode output. One possible route to controlling the spatial output of such devices is through the use of tapered waveguides [3]. For devices of a few centimetres in length, adiabatic expansion can be achieved up to widths of a few hundred microns. This leads to structures compatible with end-pumping by broad-stripe diodes or, for higher power, side-pumping by diode bars. The latter route requires a very strong absorption of the diode emission, as th...
Lasers based on planar waveguides have recently generated interest for use as scalable high-average-power sources, Here we study the thermal diffusion of Nd3+ and Gd3+ ions in YVO4 in order to obtain the essential diffusion characteristics necessary to calculate the conditions required for fabrication of waveguides suitable for laser action at 1 μm. Nd 3+ is studied both for localised doping as the active laser ion and as a potential refractive index modifier. We also choose to study Gd3+ diffusion as an index modifier in order to give the potential for separate control of the index and gain distributions.
We demonstrate an in-plane diode-stack side-pumped planar waveguide laser. For 106W of absorbed pump power, 58W of output power is obtained at 1.064μm from a monolithic 30μm-thick double-clad Nd:YAG waveguide.
