Optical amplification and photodegradation in films of spiro-quaterphenyl and its derivatives

Fluorescence spectra and optical constants in planar waveguides of spiro-quaterphenyl and two of its derivatives are investigated. Threshold of amplified spontaneous emission (ASE) and optical gain are determined. The thickness dependence of ASE spectral position, ASE threshold, and optical gain are investigated as well. Additionally, photodegradation in air and in vacuum for spiro-quaterphenyl and methoxy-spiro-quaterphenyl is compared. Films with various thicknesses (30-220 nm) have been deposited by vacuum vapor deposition. A measurement setup based on the variable stripe length method was used to determine the threshold and the optical gain using ASE. A threshold of 22±5.7 µJ/cm2, 51±2.1 µJ/cm2 and 70±10 µJ/cm2 was measured for spiro-quaterphenyl, methoxy-spiro-quaterphenyl and phenoxy-spiro-quaterphenyl respectively. At pump energy fluence of 3000 µJ/cm2, maximum gain of 107.5±7 cm−1, 104±6 cm−1 and 184±1.2 cm−1 was achieved for spiro-quaterphenyl, methoxy-spiro-quaterphenyl and phenoxy-spiro-quaterphenyl respectively.