Measurement and Modeling of Infrared Nonlinear Absorption Coefficients and Laser-induced Damage Thresholds in Ge and GaSb

Using a simultaneous fitting technique to extract nonlinear absorption coefficients from data at two pulse widths, we measure two-photon and free-carrier absorption coefficients for Ge and GaSb at 2.05 and 2.5 μm for the first time, to our knowledge. Results agreed well with published theory. Single-shot damage thresholds were also measured at 2.5 μm and agreed well with modeled thresholds using experimentally determined parameters including nonlinear absorption coefficients and temperature dependent linear absorption. The damage threshold for a single-layer Al2O3 anti-reflective coating on Ge was 55% or 35% lower than the uncoated threshold for picosecond or nanosecond pulses, respectively

Evaluation of Mn\u3csup\u3e5+\u3c/sup\u3e-doped Sr5(VO4)3F as a laser material based on excited-state absorption and stimulated-emission measurements

Excited-state absorption and stimulated-emission measurements of Mn5+-doped Sr5(VO4)3F were made with a pump-and-probe technique. Strong excited-state absorption bands were observed, corresponding to the transitions from the 1E(1D) metastable level to higher-lying singlet levels. The stimulate emission from the 1E(1D) level to the 3A2(3F) ground state is overlapped by a tail of the 1E(1D)→1T2(1D) excited-state absorption band. The cross section of the 1E(1D) → 1T2(1D) transition at 1161 nm is (1.4 ± 0.3) × 10-20 cm2 for E∥c and (2.4 ± 0.5) × 10-20 cm2 for E⊥c. The ratio between the excited-state absorption and the stimulated-emission cross section at 1161 nm is 0.52 for E∥c and 1.82 for E⊥c. Therefore laser emission is expected to be inefficient in E∥c polarization and not to be possible in E⊥c polarization. The crystal field parameters in the cubic field approximation were determined to be Dq = 1134 cm-1, B = 356 cm-1, and C = 2918 cm-1, giving Dq/B = 3.19 and C/B = 8.20. © 1997 Optical Society of America

Co2Sensing With A 1.432 Μm Nd:Yalo3Laser

A smoothly tunable 1.432 μm Nd:YAlO3 laser was assembled for potential remote sensing of atmospheric CO2 at high altitudes. Continuous laser tuning from 6982.8 to 6984.6 cm-1 was demonstrated, and CO2 absorption lines relatively free of atmospheric water absorption interference at 6983 and 6984 cm-1 were experimentally observed, confirming feasibility of atmospheric CO2 sensing

Ultrabroad Mid-Infrared Tunable Cr:Znse Channel Waveguide Laser

Operation of a Cr:ZnSe external-cavity waveguide laser is demonstrated with a CW tuning range of 700 nm from 2077-2777 nm (700 nm or 36 THz), the widest tuning range demonstrated by a waveguide laser. Narrow linewidths as low as 53 pm FWHM (3 GHz) are achieved and a maximum output power of 120 mW is attained at 2446 nm with over 15 mW available across the entire tunable range. A theoretical model is presented allowing the effect of changes to the system to be quantified in terms of laser performance; this allows the limitations of the architecture to be assessed. Good agreement is seen between the model and the experimental values obtained