Titanium dioxide films were prepared by plasma ion-assisted electron beam evaporation. Linear optical properties were investigated in terms of spectrophotometry using the beta-distributed oscillator (ß_do) model as a parametrized dispersion law. The nonlinear two-photon absorption coefficient of titanium dioxide was determined by means of the laser-induced deflection technique at a wavelength of 800 nm. The obtained values of (2–5) × 10⁻¹¹ cm/W were consistent with published experimental values for rutile as well as for simulations performed in the frames of the ß_do and Sheik–Bahae models.

Absolute measurement of residual absorption in optical coatings is steadily becoming more important in thin film characterization, in particular with respect to high power laser applications. A summary is given on the current ability of the laser induced deflection (LID) technique to serve sensitive photo-thermal absorption measurements combined with reliable absolute calibration based on an electrical heater approach. To account for different measurement requirements, several concepts have been derived to accordingly adapt the original LID concept. Experimental results are presented for prominent UV and deep UV laser wavelengths, covering a variety of factors that critically can influence the absorption properties in optical coatings e.g., deposition process, defects and impurities, intense laser irradiation and surface/interface engineering. The experimental findings demonstrate that by combining high sensitivity with absolute calibration, photo-thermal absorption measurements are able to be a valuable supplement for the characterization of optical thin films and coatings.

The surface absorption of ${\mathrm{CaF}}_2$ at 193 nm after surface treatment by ion beam figuring (IBF) and the subsequent antireflective (AR) coating process was investigated by using the laser-induced deflection technique. In comparison to a standard pitch polishing, enhanced surface absorption (subsurface damage) is observed after IBF treatment. However, after AR coating deposition, the total surface absorption of IBF treated samples does not exceed values obtained for pitch polished samples. The experimental results provide indication that IBF treatment yields both fluorine displacement and deficiency in the ${\mathrm{CaF}}_2$ subsurface region, which is annealed during the coating process by the high temperature and the fluorine supply from the fluoride coating materials, respectively.

The Sandwich concept of the laser induced deflection (LID) technique is applied to characterize nonlinear optical crystals from the near infrared to the deep UV wavelengths. In particular, nonlinear bulk absorption at 355nm and 266nm is investigated in BBO, CLBO and LBO, respectively.

The laser induced deflection (LID) technique for absolute absorption measurements is introduced. From the general principle, several concepts are derived for measurements in optical materials, coatings and fibers. Experimental results will cover nonlinear optical crystals, optical coatings and fiber Bragg gratings.