An Ultra-Narrow Linewidth Solution-Processed Organic Laser

Abstract

Optically pumped lasers based on solution-processed thin-film gain media have recently emerged as low-cost, broadly tunable, and versatile active photonics components that can fit any substrate and are useful for, e.g., chemo-or biosensing or visible spectroscopy. Although single-mode operation has been demonstrated in various resonator architectures with a large variety of gain media-including dye-doped polymers, organic semiconductors, and, more recently, hybrid perovskites-the reported linewidths are typically on the order of a fraction of a nanometer or broader, i.e., the coherence lengths are no longer than a few millimeters, which does not enable high-resolution spectroscopy or coherent sensing. The linewidth is fundamentally constrained by the short photon cavity lifetime in the standard resonator geometries. We demonstrate here a novel structure for an organic thin-film solid-state laser that is based on a vertical external cavity, wherein a holographic volume Bragg grating ensures both spectral selection and output coupling in an otherwise very compact (∼cm 3) design. Under short-pulse (0.4 ns) pumping, Fourier-transform-limited laser pulses are obtained, with a full width at half-maximum linewidth of 900 MHz (1.25 pm). Using 20-ns-long pump pulses, the linewidth can be further reduced to 200 MHz (0.26 pm), which is four times above the Fourier limit and corresponds to an unprecedented coherence length of 1 m. The concept is potentially transferrable to any type of thin-film laser and can be ultimately made tunable it also represents a very compact alternative to bulky grating systems in dye lasers.

Publication Date

2-12-2016

Publication Title

Light: Science and Applications

Volume

5

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1038/lsa.2016.26

Socpus ID

84958093292 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/84958093292

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