eprintid: 36159 rev_number: 40 eprint_status: archive userid: 608 dir: disk0/00/03/61/59 datestamp: 2010-10-15 08:16:19 lastmod: 2021-12-20 00:59:29 status_changed: 2016-06-09 11:04:26 type: proceedings_section metadata_visibility: show item_issues_count: 0 creators_name: Marsh, RJ creators_name: Leonczek, ND creators_name: Armoogum, DA creators_name: Porres, L creators_name: Mongin, O creators_name: Blanchard-Desce, M creators_name: Bain, AJ title: Stimulated emission depletion dynamics in push-push polyenes ispublished: pub divisions: UCL divisions: B04 divisions: C06 divisions: F60 keywords: two-photon absorption, stimulated emission depletion, fluorescence anisotropy, polarisation vibrational relaxation, 2-photon absorption, quadrupolar chromophores, fluorescence anisotropy, imaging microscopy, pull dipolar, fluorophores, spectroscopy, molecules, states, derivatives note: Copyright © 2004 Society of Photo Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited. abstract: Two-photon fluorescence polarisation and stimulated emission depletion dynamics are investigated in three high two -photon cross-section push-push polyenes: OM62, LP79 and OM77 and compared to the behaviour of a standard fluorophore (rhodamine 6G). Two-photon fluorescence anisotropy measurements (R(O) and Omega) were undertaken using picosecond time-correlated single photon counting (TCSPC). For OM62 and LP79 these are consistent with a diagonal two-dimensional transition tensor with S-XX>S-YY. For OM77 the contribution of off-diagonal elements (S-XY & S-YX) appears significant. Two-photon fluorescence anisotropy decay data is combined with streak camera measurements of excited state population depletion to determine stimulated emission cross sections and ground state vibrational relaxation times. Cross-sections for STED in all three polyenes were found to be significantly higher than those for rhodamine 6G. The efficiency of STED is however dependent on the degree to which the S-1-->S-0 transition is saturated by the DUMP pulse; this is mediated by fast ground state vibrational relaxation. Of the three polyenes.. LP79 is seen to combine a large stimulated emission cross-section (c.a. 13sigma(r6G)) with rapid ground state relaxation (tau(R)=240fs). date: 2004-10-14 date_type: published publisher: Society of Photo-Optical Instrumentation Engineers (SPIE) official_url: http://dx.doi.org/10.1117/12.564433 vfaculties: VMPS oa_status: green full_text_type: pub language: eng primo: open primo_central: open_green verified: verified_manual elements_source: Scopus elements_id: 50728 doi: 10.1117/12.564433 lyricists_name: Armoogum, Daven lyricists_name: Bain, Angus lyricists_id: DAARM27 lyricists_id: AJBAI08 actors_name: Bain, Angus actors_name: Allington-Smith, Dominic actors_id: AJBAI08 actors_id: DAALL44 actors_role: owner actors_role: impersonator full_text_status: public series: Proceedings of SPIE publication: NANOPHOTONIC MATERIALS volume: 5510 place_of_pub: Denver, CO, USA event_title: Nanophotonic Materials event_location: Denver, CO event_dates: 02 August 2004 - 03 August 2004 institution: Conference on Nanophotonic Materials isbn: 0819454486 issn: 0277-786X book_title: Nanophotonic Materials editors_name: Andrew, DL editors_name: Cao, GZ editors_name: Gaburro, Z citation: Marsh, RJ; Leonczek, ND; Armoogum, DA; Porres, L; Mongin, O; Blanchard-Desce, M; Bain, AJ; (2004) Stimulated emission depletion dynamics in push-push polyenes. In: Andrew, DL and Cao, GZ and Gaburro, Z, (eds.) Nanophotonic Materials. Society of Photo-Optical Instrumentation Engineers (SPIE): Denver, CO, USA. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/36159/1/Bain_117_1_STED_PushPushPolyenes.pdf