| A silver coated hollow glass fiber with a core diameter of 250 mum is studied for beam transport and nonlinear optical applications at 800 nm using a femtosecond Ti:sapphire laser. To reduce the losses, the inner glass surface of the waveguide is coated with a thin film of silver by a liquid phase deposition process. The measured transmission loss of the straight silver coated hollow fiber, 0.44 dB/m, is lower than the transmission loss of a similar fused silica hollow fiber, 1.94 dB/m. Beam diameter measurements indicate that a single HE11 mode propagates from output of the waveguide into free space. The bending loss of this waveguide was measured for bending radii of 30, 50, and 100 cm and compared to the theoretical values. Numerical modeling and experimental results for optical compression of femtosecond pulses are presented. Input pulses with energy of 250muJ and duration of 110 fs were compressed to 20 fs with energy of 220 muJ using the silver coated hollow fiber, filled with argon, and a prism pair. The same experiment was performed for the fused silica hollow fiber which produced 20 fs pulses with energy of 190 muJ. There was close agreement between the pulse compression numerical and experimental results. Nonlinear ellipse rotation for pulse contrast enhancement was also studied using the silver coated waveguide. The results were similar to those obtained for the fused silica waveguide, but with higher transmission. |
