Two-photon pumped cavity lasing in novel dye doped bulk matrix rods

TLDR

The trans‑4‑[p‑(N‑ethyl‑N‑hydroxyethylamino)styryl]‑N‑methylpyridyl dye exhibits a markedly larger two‑photon absorption cross‑section and stronger upconversion fluorescence than conventional dyes such as rhodamine when excited with near‑infrared light. Two‑photon pumped cavity lasing was realized by Q‑switched Nd:YAG laser excitation at 1.06 µm (≈10 ns pulses), producing 600 nm output pulses of 3–6 ns duration. The 7 mm doped polymer rod achieved a 3.5 % conversion efficiency at 1.3 mJ pump energy and maintained lasing for over 40 000 pulses at a 2 Hz repetition rate.

Abstract

Trans-4-[p-(N-ethyl-N-hydroxyethylamino)styryl]-N-methylpyridi that possesses a much greater two-photon absorption cross section and much stronger upconversion fluorescence emission than common organic dyes (such as rhodamine), when excited with near infrared laser radiation. Utilizing ASPT doped bulk polymer rods, two-photon pumped frequency upconverted cavity lasing has been accomplished using a Q-switched Nd:YAG laser as the pump source. The wavelength and pulse duration were ∼600 nm and 3–6 ns, respectively, for the cavity lasing; whereas the corresponding values for pump pulses were 1.06 μm and ∼10 ns, respectively. For a 7 mm long sample rod with a dopant concentration d0=8×10−3 M/L, the conversion efficiency from the absorbed pump energy to the cavity lasing output was ∼3.5% at a pump energy level of 1.3 mJ. The lasing lifetime, in terms of pulse numbers, was more than 4×104 pulses at 2 Hz repetition rate and room temperature.