Amplified spontaneous emission in the near infrared from a dye-doped polymer thin film

Although optical gain and lasing has been observed in the solid state for numerous organic molecules emitting at visible wavelengths, this is not the case in the infrared. Here, we show line-narrowing due to amplified spontaneous emission in the near infrared (960 nm) from a solid state organic thin film, made by spin-coating, a blend of the laser dye IR-140 and the polymer poly(methylmethacrylate). Line-narrowing becomes evident for excitation densities above 4.8 mJ cm−2, and is tunable between 920 and 970 nm, with a maximum gain value of 6.6 cm. Preliminary results using other near infrared-emitting dyes suggest that this may be a general approach