Opticution
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Opticution is the term given to the damaging beyond viability of biological samples that are manipulated via optical traps, most commonly optical tweezers. The term was coined by Arthur Ashkin, who developed optical tweezers at Bell Labs in the 1970s and 80s. As different biological samples absorb different wavelengths, choosing the proper laser frequency can help to minimize the danger of opticution. Near-infrared diode lasers are a popular choice because of this and their relative inexpensiveness.
Recent work by Neumann (Characterization of photodamage to Escherichia coli in optical traps; BIOPHYSICAL JOURNAL 77 (5): 2856-2863 NOV 1999) has shown that for continuous lasers, such as those employed in optical traps, the damage seems to be a single-photon process (as opposed to the two-photon process found in pulsed lasers). Furthermore, the damage is related to the presence of oxygen, and use of an oxygen-scrubbing system can reduce optical damage indefinitely.
