Wavelength-versatile visible and UV sources based on crystalline Raman lasers

Ultraviolet photoluminescence in Gd-doped silica and phosphosilicate fibers

“…Currently, UV sources consist mostly of gas lasers, 5 lamps, or diodes 1 or rely on nonlinear optical processes, such as third/fourth harmonic generation or optical parametric oscillators (OPOs). 6,7 Fiberized laser sources could be an attractive alternative to conventional UV sources. Fiber based light sources exhibit excellent beam quality, extraordinary brightness, small detrimental thermal effects, and high temporal stability.…”

“…Simultaneously, silica glass, the host material, has various advantages including transparency in the UV down to λ ∼ 200 nm, 11,12 extraordinary mechanical strength, strong chemical and radiation resistance, and compatibility with existing silica-based components. The silica network has a high phonon energy (ṽ ∼ 1100 cm 1 ); therefore, transitions among the 6 D J , 6 I J and 6 P J energy levels in Gd 3+ -doped silica tend to be dominated by non-radiative multi-phonon relaxation due to the small energy gaps. Previous studies of Gd-doped samples in film, bulk, and powder form under electron-beam, vacuum ultraviolet (VUV), and X-ray excitation [13][14][15] suggest that the emission at λ ∼ 312 nm, given by the 6 would be a promising candidate for the generation of light in the UV.…”

“…The silica network has a high phonon energy (ṽ ∼ 1100 cm 1 ); therefore, transitions among the 6 D J , 6 I J and 6 P J energy levels in Gd 3+ -doped silica tend to be dominated by non-radiative multi-phonon relaxation due to the small energy gaps. Previous studies of Gd-doped samples in film, bulk, and powder form under electron-beam, vacuum ultraviolet (VUV), and X-ray excitation [13][14][15] suggest that the emission at λ ∼ 312 nm, given by the 6 would be a promising candidate for the generation of light in the UV. The lifetime of the 6 P 7/2 level has been found to be 5 ms in a sol-gel sample containing ∼3 mol.…”

“…Photoluminescence spectra for optical fiber bundles and fiber preforms were recorded and compared. Emissions at 312 nm (phosphosilicate) and 314 nm (pure silica) were observed when pumping to the Gd 3+ 6 D J , 6 I J , and 6 P J=5/2, 3/2 energy levels. Oxygen deficient center was observed in solution doping sample with a wide absorption band centered at around 248 nm not affecting pumping to 6 …”

Spectral broadening in continuous-wave intracavity Raman lasers

“…Continuous-wave (CW) intracavity Raman lasers can be compact and convenient sources of radiation in regions of the spectrum that are difficult to reach with other laser sources [1].…”