Nanosecond laser damage resistance of differently prepared semi-finished parts of optical multimode fibers

Breakdown limits of optical multimode fibers for the application of nanosecond laser pulses at 532nm and 1064nm wavelength

“…Multi pulse ablation thresholds (308 nm, 33 ns) of F th % 20 J/cm 2 for polished Suprasil samples (Heraeus) with an average roughness of 2 nm and F th % 7 J/cm 2 for specimens featuring a roughness of 40 nm were reported [2]. These findings agree with observations of a change of single pulse LIDT values (1064 nm, 15 ns) from 320 J/cm 2 to 150 J/cm 2 for Heraeus F300 samples and surface roughnesses of about 1 nm and 70 nm, respectively [11].…”

“…Laser focus diameters (second moment) in the interaction region of 2w = 50 AE 2 mm (1064 nm) and 2w = 30 AE 1 mm (532 nm) were achieved. More details about the experimental equipment can be found in [11,14]. The maximum laser fluence F 0 was calculated according to [13]:…”

“…Only a few papers were published on the influence of the existing (or even laser-induced) surface quality on LIDT [2,10,11]. Multi pulse ablation thresholds (308 nm, 33 ns) of F th % 20 J/cm 2 for polished Suprasil samples (Heraeus) with an average roughness of 2 nm and F th % 7 J/cm 2 for specimens featuring a roughness of 40 nm were reported [2].…”

“…Many studies on the interaction of powerful laser pulses with fused silica surfaces have been performed during the last decades [1][2][3][4][5][6][7][8][9][10][11]. Basically, fused silica shows high laser-induced damage thresholds (LIDT) due to its large band gap ($8 eV) for an impact of laser pulses with durations down to the femtosecond scale and wavelengths ranging from the ultraviolet to the infrared.…”

Investigation of optical fibers for coherent anti-Stokes Raman scattering (CARS) spectroscopy in reacting flows

“…Lowdermilk and Milam reported a higher surface damage threshold for optically polished silica of 30-50 J/cm 2 using 3-ns pulses at 1,064 nm (Lowdermilk and Milam 1981). Mann et al reported the surface damage threshold of polished suprasil silica to be 150-320 J/cm 2 using 1-ns pulses at 1,064 nm (Mann et al 2007). Smith and Do showed that the surface damage threshold (3,800 J/cm 2 ) could be made the same as the bulk damage threshold through the use of an alumina or silica surface polish .…”