000224527 001__ 224527
000224527 005__ 20181203024521.0
000224527 0247_ $$2doi$$a10.1038/ncomms13383
000224527 022__ $$a2041-1723
000224527 02470 $$2ISI$$a000388078100001
000224527 037__ $$aARTICLE
000224527 245__ $$aMid-infrared ultra-high-Q resonators based on fluoride crystalline materials
000224527 260__ $$bNature Publishing Group$$c2016$$aLondon
000224527 269__ $$a2016
000224527 300__ $$a8
000224527 336__ $$aJournal Articles
000224527 520__ $$aThe unavailability of highly transparent materials in the mid-infrared has been the main limitation in the development of ultra-sensitive molecular sensors or cavity-based spectroscopy applications. Whispering gallery mode microresonators have attained ultra-high-quality (Q) factor resonances in the near-infrared and visible. Here we report ultra-high Q factors in the mid-infrared using polished alkaline earth metal fluoride crystals. Using an uncoated chalcogenide tapered fibre as a high-ideality coupler in the mid-infrared, we study via cavity ringdown technique the losses of BaF2, CaF2, MgF2 and SrF2 microresonators. We show that MgF2 is limited by multiphonon absorption by studying the temperature dependence of the Q factor. In contrast, in SrF2 and BaF2 the lower multiphonon absorption leads to ultra-high Q factors at 4.5 mu m. These values correspond to an optical finesse of F > 1 x 10(5), the highest value achieved for any type of mid-infrared resonator to date.
000224527 700__ $$0248069$$g246186$$aLecaplain, C.
000224527 700__ $$0248145$$g222695$$aJaverzac-Galy, C.
000224527 700__ $$aGorodetsky, M. L.
000224527 700__ $$aKippenberg, T. J.$$g182444$$0244694
000224527 773__ $$j7$$tNature Communications$$q13383
000224527 909C0 $$0252348$$pLPQM
000224527 909CO $$particle$$ooai:infoscience.tind.io:224527$$pSB$$pSTI
000224527 917Z8 $$x222695
000224527 937__ $$aEPFL-ARTICLE-224527
000224527 973__ $$rNON-REVIEWED$$sPUBLISHED$$aEPFL
000224527 980__ $$aARTICLE