Advances in organic polariton lasers

Organic semiconductors are an attractive class of semiconductor combining simple fabrication with the scope to tune properties by changing the structure. Their high oscillator strength and exciton binding energy make them attractive candidates for strong light-matter coupling, and polariton lasers operating at room temperature have been demonstrated. Many of these lasers operate at high thresholds (>100 uJ/cm2). We have explored fluorene oligomers and polymers as a route to much lower thresholds. We demonstrate low-threshold (<20 µJ/cm2) polariton lasing in a range of fluorene-based materials. Building on these results we have explored 1D and 2D lattices of polariton condensates. In the 2D case we observe a polariton condensate 2-3 µm from the pump spots, showing that polaritons can travel much further than excitons in organic semiconductors.