Study of spontaneous and induced absorption in amorphous Ta2O5 and SiO2 dielectric thin films

Tantalum pentoxide (Ta2O5) and silicon dioxide (SiO2) are common high-index and low-index materials used in dielectric optical coatings for high average-power lasers since high-density sputtered oxide films with absorption losses at near- and mid-infrared wavelengths of less than 1 ppm can be obtained. These oxides have been chosen to investigate the spontaneous and optically induced absorption at λ0 = 1064 nm that occurs due to simultaneous illumination at shorter wavelengths. The effect is measured using the photothermal common-path interferometric technique. This technique is capable of detecting sub-ppm levels of optical absorption and tracking its changes at a given wavelength when a second laser beam is also incident on a thin film oxide sample. In this work, dual beam experiments are employed to assess changes in the optical absorption at λ0 = 1064 nm in ion beam sputtered Ta2O5 and SiO2 thin films deposited on fused silica substrates, with stimulating illumination λ1 ranging from λ1 = 266 nm to λ1...

[1]  J. P. Gordon,et al.  Long‐Transient Effects in Lasers with Inserted Liquid Samples , 1965 .

[2]  J. Whinnery,et al.  New thermooptical measurement method and a comparison with other methods. , 1973, Applied optics.

[3]  J. H. Thomas.  uv‐stimulated photocurrent spectroscopy and trapping kinetics of a 2.1‐eV trap in anodic Ta2O5 films , 1974 .

[4]  E. Bassous,et al.  Transmission, photoconductivity, and the experimental band gap of thermally grown SiO 2 films , 1979 .

[5]  T. Unagami,et al.  Electron trapping levels in rf‐sputtered Ta2O5 films , 1983 .

[6]  M. Nakata,et al.  Two-step annealing technique for leakage current reduction in chemical-vapor-deposited Ta/sub 2/O/sub 5/ film , 1989, IEEE Electron Device Letters.

[7]  N. D. Rooij,et al.  Reduced light sensibility in optimized Ta2O5-ISFET structures , 1991 .

[8]  T. Minami,et al.  Effects of UV-irradiation on the formation of oxide thin films from chemically modified metal-alkoxides , 1994 .

[9]  S. Bialkowski,et al.  Diffraction effects in single- and two-laser photothermal lens spectroscopy. , 1997, Applied optics.

[10]  Ian W. Boyd,et al.  Thin tantalum oxide films prepared by 172 nm Excimer lamp irradiation using sol–gel method , 1998 .

[11]  H. Hosono,et al.  Photochemical processes induced by 157-nm light in H(2)-impregnated glassy SiO(2):OH. , 1999, Optics letters.

[12]  Ian W. Boyd,et al.  Photo-induced growth of dielectrics with excimer lamps , 2001 .

[13]  Kai Starke,et al.  Femtosecond laser pulse induced breakdown in dielectric thin films , 2001 .

[14]  M. Fejer,et al.  Green-induced infrared absorption in MgO doped LiNbO3 , 2001 .

[15]  Martin M. Fejer,et al.  Thermal noise in interferometric gravitational wave detectors due to dielectric optical coatings , 2001, gr-qc/0109073.

[16]  Guolong Tan,et al.  Optical Properties and London Dispersion Forces of Amorphous Silica Determined by Vacuum Ultraviolet Spectroscopy and Spectroscopic Ellipsometry , 2003 .

[17]  N. Kaiser,et al.  Optical interference coatings , 2003 .

[18]  Alban Remillieux,et al.  Titania-doped tantala/silica coatings for gravitational-wave detection , 2006 .

[19]  Y. Wang,et al.  Assessing the impact of atomic oxygen in the damage threshold and stress of Hafnia films grown by ion beam sputter deposition , 2007, SPIE Laser Damage.

[20]  Martin M. Fejer,et al.  Photothermal common-path interferometry (PCI): new developments , 2009, LASE.

[21]  Roger Route,et al.  Advances in ion beam sputtered Sc2O3 for optical interference coatings , 2010, Laser Damage.

[22]  Carmen S. Menoni,et al.  Spontaneous and induced absorption in amorphous Ta2O5 dielectric thin films , 2011, Laser Damage.