The present invention discloses a new class of triarylsulfonium salt photoacid generators (PAGs), which are thermally stable and can be activated by long wavelength UV or visible light. The sulfonium PAGs of the present invention are additionally soluble in monomers that can be polymerized by cationic polymerization chemistry, and mixtures of said sulfonium PAGs and monomers can be stored for long periods of time without undergoing polymerization. Furthermore, typical holographic recording media comprising one of these sulfonium PAGs, polymerizable monomer(s), a sensitizing dye, and a binder can be stored for long periods of time without exhibiting significant loss of recording sensitivity. Preferred sulfonium PAGs of the present invention are sulfonium PAGs substituted with one or more fluoro or fluoroalkyl groups.