Operational Regimes in Picosecond and Femtosecond Pulse-Excited Ultrahigh Vacuum SERS.
J Phys Chem Lett
; 7(15): 2971-6, 2016 Aug 04.
Article
in En
| MEDLINE
| ID: mdl-27428724
ABSTRACT
We report a systematic study performed in ultrahigh vacuum designed to identify the laser excitation regimes in which plasmonically enhanced ultrashort pulses may be used to nondestructively probe surface-bound molecules. A nondestructive, continuous-wave spectroscopic probe is used to monitor the effects of four different femtosecond- and picosecond-pulsed beams on the SER signals emanating from molecular analytes residing within plasmonically enhanced fields. We identify the roles of plasmonic amplification and alignment with a molecular electronic transition on the observed changes in the SER signals. Our results indicate that overlap of the laser wavelength with the plasmon resonance is the dominant contributor to signal degradation. In addition, signal loss for a given irradiation condition is observed only for molecules residing in hot spots above a threshold enhancement. Identification of suitable laser energy density ranges demonstrates the importance of considering these parameters when implementing SERS in the presence of pulsed irradiation.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
J Phys Chem Lett
Year:
2016
Document type:
Article
Affiliation country:
United States