Flexible and ultra-lightweight polymer membrane lasers

TLDR

Organic semiconductors enable lightweight, mechanically flexible optoelectronic devices, yet most organic semiconductor lasers remain rigid because they require a support substrate. This work seeks to fabricate substrate‑free, ultrathin (<500 nm) organic distributed feedback lasers that are ultralight (m/A < 0.5 g m⁻²) and highly flexible. The authors use a simple fabrication process to produce membrane‑based lasers that can be transferred onto arbitrary substrates, such as a banknote, where the lasing spectrum can serve as a security feature. The resulting membrane lasers have pump thresholds and emission intensities within permissible ocular exposure limits and are demonstrated on contact lenses as wearable security tags.

Abstract

Organic semiconductors enable the fabrication of a range of lightweight and mechanically flexible optoelectronic devices. Most organic semiconductor lasers, however, have remained rigid until now, predominantly due to the need for a support substrate. Here, we use a simple fabrication process to make membrane-based, substrate-less and extremely thin (<500 nm) organic distributed feedback lasers that offer ultralow-weight (m/A<0.5 gm-2) and excellent mechanical flexibility. We show operation of the lasers as free-standing membranes and transfer them onto other substrates, e.g. a banknote, where the unique lasing spectrum is readily read out and used as security feature. The pump thresholds and emission intensity of our membrane lasers are well within the permissible exposures for ocular safety and we demonstrate integration on contact lenses as wearable security tags.