J.Biomed. Opt. 17, 101502 (2012)

Credit: © 2012 SPIE

Laser-assisted surgery based on the multiphoton absorption of near-infrared laser light has significant potential for high-precision surgery at various depths within cells and tissues. Although low-energy femtosecond pulses can be used to achieve safe, highly localized and ultraprecise manipulation of subcellular organelles, conventional systems for laser micro- and nanoprocessing employ micro- to millijoule energies, which can induce destructive effects in cells. Karsten König and co-workers have now demonstrated an ultrashort femtosecond laser scanning microscope that can perform precise (sub-100-nm spatial resolution) surgery of human cells and metaphase chromosomes. The researchers used a mode-locked, 85 MHz repetition rate Ti:sapphire laser with an 'M'-shaped ultrabroadband spectrum (maxima at around 770 nm and 830 nm), with pulse durations of between 12 fs and 3 ps. Such picojoule pulses were sufficient to induce sub-100-nm multiphoton ablation effects, which are nearly an order of magnitude smaller than the wavelength of light used. The researchers say that this work may lead to compact, cost-effective laser sources for use in future femtosecond laser nanoprocessing and imaging microscopes.