2,089 research outputs found
Low-loss Ti:sapphire waveguides fabricated by pulsed laser deposition
No full textWe report the fabrication and characterisation of Ti:sapphire films epitaxially grown on c-cut sapphire substrates by pulsed laser deposition (PLD). Deposition conditions have been studied extensively and optimised in order to produce high-performance optical waveguides. In particular we have studied the effects of different values of oxygen pressure, background gases and substrate temperature on the resultant surface roughness, composition, crystallinity, fluorescence and waveguide losses. For instance we found that Ti:sapphire films deposited in Ar feature higher fluorescence than those grown in O2 and N2 (see Figure 1) under the same deposition conditions: laser fluence F ~ 3.3 J/cm2, laser repetition rate f = 20 Hz, substrate temperature T ~ 1050°C, gas pressure P ~ 2.10-3 mbar, target-substrate distance d = 4 cm
Crystal waveguide lasers, liquid epitaxy and ion-implantation
No full textFabricating 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
End-pumped passively Q-switched Yb:YAG double-clad waveguide laser
No full textWe 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 4W polarization-coupled, broad-stripe diode-pumped lasers, we obtained 30µJ pulses of 16ns 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
- …
