Title: Energy transfer networks: Quasicontinuum photoluminescence linked to high densities of defects

Abstract

In a series of studies related to laser-induced damage of optical materials and deposition of plastics, we discovered a broadly emitting photoluminescence with fast lifetimes that we termed quasicontinuum photoluminescence (QC-PL). Here in this paper, we suggest that a high density of optically active defects leads to QC-PL, where interactions between defects affect the temporal and spectral characteristics of both excitation and emission. We develop a model that predicts the temporal characteristics of QC-PL, based on energy transfer interactions between high densities of defects. Our model does not explain all spectral broadening and redshifts found in QC-PL, since we do not model spectral changes in defects due to proximity to other defects. However, we do provide an example of a well-defined system that exhibits the QC-PL characteristics of a distribution in shortened lifetimes and broadened, redshifted energy levels: an organic chromophore (fluorescein) that has been dried rapidly on a fused silica surface. Recently, we showed that regions of fused silica exposed to up to 1 billion high-fluence laser shots at 351 rm nm at subdamage fluences exhibit significant transmission losses at the surface. Here, we find that these laser-exposed regions also exhibit QC-PL. Increases in the density of induced defectsmore » on these laser-exposed surfaces, as measured by the local transmission loss, lead to decreases in the observed lifetime and redshifts in the spectrum of the QC-PL, consistent with our explanation for QC-PL. In conclusion, we have found QC-PL in an increasing variety of situations and materials, and we believe it is a phenomenon commonly found on surfaces and nanostructured materials.« less

Authors:

Laurence, Ted A. ^[1]; Ly, Sonny ^[1]; Bude, Jeff D. ^[1]; Baxamusa, Salmaan H. ^[1]; Lepró, Xavier ^[1]; Ehrmann, Paul ^[1]

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+ Show Author Affiliations

1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Materials Science Division

Publication Date:

Mon Nov 06 00:00:00 EST 2017

Research Org.:

Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

Sponsoring Org.:

USDOE

OSTI Identifier:

1409993

Alternate Identifier(s):

OSTI ID: 1407446

Report Number(s):

LLNL-JRNL-733134
Journal ID: ISSN 2475-9953; PRMHAR; TRN: US1702965

Grant/Contract Number:  

AC52-07NA27344

Resource Type:

Accepted Manuscript

Journal Name:

Physical Review Materials

Additional Journal Information:

Journal Volume: 1; Journal Issue: 6; Journal ID: ISSN 2475-9953

Publisher:

American Physical Society (APS)

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS