The use of commercial long-wavelength (>650 nm) laser dyes in many biophotonic applications has several important limitations, including low absorption at the standard pump wavelength (532 nm) and poor photostability. A research group headed by L. Cerdán from IQFR, in collaboration with researchers from Universidad Complutense de Madrid and Universidad del Pais Vasco, have demostrated that the use of Förster type (FRET) energy transfer can overcome these problems to enable efficient, stable near-IR lasing in a colloidal suspension of latex nanoparticles containing a mixture of Rhodamine 6G and Nile Blue dyes.

Reference: “FRET-assisted laser emission in colloidal suspensions of dye-doped latex nanoparticles,“ L. Cerdán,* E. Enciso, V. Martín, J. Bañuelos, I. Lopez Arbeloa, A. Costela and I. García-Moreno;  Nature Photonics 2012 DOI: 10.1038/ NPHOTON.2012.201
http://www.nature.com/nphoton/journal/vaop/ncurrent/full/nphoton.2012.201.html