The two-photon absorption spectrum of ruby and its role in distributed optical fibre sensing

• Published in: Applied physics. B, Lasers and optics Vol. 103; no. 1; pp. 113 - 116
• Main Authors: Dalzell, C. J., Han, T. P. J., Ruddock, I. S.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.04.2011
• Subjects: Absorption spectra; Detection; Engineering; Excitation; Illumination; Lasers; Optical Devices; Optical fibers; Optics; Photonics; Physical Chemistry; Physics; Physics and Astronomy; Quantum Optics; Ruby; Wavelengths; Extraordinary Polarisation; State Population Density; Optical Parametric Oscillator; Ruby; Short Wavelength Peak
• ISSN: 0946-2171; 1432-0649
• DOI: 10.1007/s00340-010-4207-3

The two-photon absorption spectrum and cross-section ( δ ) for ruby (Cr 3+ :sapphire) have been measured over the 0.8–1.2 μm wavelength range at 25°C. Absolute values of δ were obtained by comparing the fluorescence yield for two-photon excitation with that for single-photon excitation of the same ionic transition under identical illumination conditions. The maximum values of δ are 4.6×10 −3  GM for o-polarisation and 5.9×10 −3 GM for e-polarisation at 840 nm. The relevance of these measurements to distributed optical fibre sensing is briefly discussed.