The lines on the graphs indicate calculations for anthracene of the lower and middle polariton (LP, MP) branches for anthracene along two different lattice directions (a,b). Also shown by the bold dashed lines are the cavity resonance lines. The graded color smudge along the LPb branch is the dispersion of emission intensity clearly showing that the E-angle dependence is consistent with polariton emission. Above threshold, the angular distribution of emission is quite limited compared to below threshold, showing a tendency of the polarition population to “condense”, following a Boltzmann, or Bose-Einstein dependince. The insets are the transverse emission patterns both below and above threshold showing an interesting bimodal appearance above threshold. The bars in the insets are 200 um.
The objective of this project is to demonstrate polariton lasing from an organic single crystal. To accomplish this a high Q optical microcavity was fabricated via cold welding. The cavity gap was then infused with anthracene and angular emission as a function of ultra-fast optical pump intensity was observed. This resulted in the first observation of room temperature polariton laser emission, including potential BEC of polaritons. This revealed potential for realizing very low threshold, even electrically pumped lasing in organics.
S. Kena-Cohen, S.R. Forrest; University of Michigan
Work performed in the U Michigan Lurie Nanofabrication Lab
