Excitation of optically trapped single particles using femtosecond pulses
- University of Florida, Gainesville, FL (United States); University of Florida
- University of Florida, Gainesville, FL (United States)
Excitation from optically trapped particles is examined through laser-induced breakdown spectroscopy following interactions with mJ-level fs pulses. Optical emissions from sub-ng ablation of precisely positioned cupric oxide microparticles are used as a method to spatially resolve laser–particle interactions resulting in excitation. External focusing lenses are often used to change the dynamics of nonlinear self-focusing of fs pulses to form laser filaments or, alternatively, to form very intense air plasmas. Given the significant implications external focusing has on laser propagation and plasma conditions, single-particle emissions are studied with focusing lenses ranging from 50 to 300 mm. It is shown that, while single particles are less excited at longer focal lengths due to limited energy transfer through laser–particle interactions, the cooler plasma results in a lower thermal background to reveal resolved single-shot emission peaks. Furthermore, by developing an understanding in the fundamental interaction that occurs between single particles and fs pulses and filaments, practical improvements can be made for atmospheric remote sensing of low-concentration aerosols.
- Research Organization:
- University of Florida, Gainesville, FL (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA), Office of Defense Nuclear Nonproliferation
- Grant/Contract Number:
- NA0004142
- OSTI ID:
- 2372620
- Journal Information:
- Optics Letters, Journal Name: Optics Letters Journal Issue: 8 Vol. 49; ISSN 0146-9592
- Publisher:
- Optical Society of America (OSA)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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