Time-resolved measurements of picosecond optical breakdown

Zysset, B.; Fujimoto, James G.; Deutsch, Thomas F.

doi:10.1007/bf00692139

Cited by 109 publications

(48 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The threshold fluence in the stroma is only slightly higher than that measured on the corneal surface [131. As compared to other threshold measurements with longer pulses [5,13,14,16], both measurements support earlier observations that the optical breakdown threshold is proportional to the square root of the pulse duration.…”

Section: Resultssupporting

confidence: 86%

Time-resolved observations of shock waves and cavitation bubbles generated by femtosecond laser pulses in corneal tissue and water

et al. 1996

View full text Add to dashboard Cite

Background and Objective Photodisruption in ocular media with high power pulsed lasers working at non‐absorbing frequencies have become a well established surgical tool since the late seventies. Shock waves and cavitation bubbles generated by the optical breakdown may strongly influence the surgical effect of photodisruptive lasers. We have investigated the shock wave and cavitation bubble effects of femtosecond laser pulses generated during photodisruption in corneal tissue and water. The results are compared to those obtained with longer laser pulses. Study Design/Materials and Methods Laser pulses with 150 fs duration at ∼620 nm wavelength have been focused into corneal tissue and water to create optical breakdown. Time‐resolved flash photography has been used to investigate the dynamics of the generated shock waves and cavitation bubbles. Results A rapid decay of the shock waves is observed in both materials with similar temporal characteristics and with a spatial range considerably smaller than that of shock waves induced by picosecond (or nanosecond) optical breakdown. Cavitation bubbles are observed to develop more rapidly and to reach smaller maximum diameter than those generated by longer pulses. In corneal tissue, single intrastromal cavitation bubbles generated by femtosecond pulses disappear within a few tens of seconds, notably faster than cavitation bubbles generated by picosecond pulses. Conclusions The reduced shock wave and cavitation bubble effects of the femtosecond laser result in more localized tissue damage. Therefore, a more confined surgical effect should be expected from a femtosecond laser than that from picosecond (or nanosecond) lasers. This indicates a potential benefit from the applications of femtosecond laser technology to intraocular microsurgery. © 1996 Wiley‐Liss, Inc.

show abstract

Section: Resultssupporting

confidence: 86%

Time-resolved observations of shock waves and cavitation bubbles generated by femtosecond laser pulses in corneal tissue and water

et al. 1996

View full text Add to dashboard Cite

show abstract

“…The influence of medium (ionization energy, impurity level and absorption) as well as beam (wavelength, pulse width, spot size, and polarization) characteristics on irradiance threshold has been the subject of several theoretical as well as experimental studies [11][12][13][14][15][16]. These investigations were primarily motivated to produce the same surgical effect in ophthalmic laser surgery applications at lower pulse energies and with less collateral tissue damages [17][18][19][20] and therefore have so far concentrated predominantly on transparent and low absorbing tissues. The mechanisms of laser tissue interactions have not been thoroughly studied in the transition regime from multiphoton to thermal initiation pathways in low to very high absorbing samples.…”

Section: Discussionmentioning

confidence: 99%

Influence of absorption induced thermal initiation pathway on irradiance threshold for laser induced breakdown

Varghese

Bonito

Jurna

et al. 2015

Biomed. Opt. Express

View full text Add to dashboard Cite

Abstract:We investigated the influence of thermal initiation pathway on the irradiance threshold for laser induced breakdown in transparent, absorbing and scattering phantoms. We observed a transition from laserinduced optical breakdown to laser-induced thermal breakdown as the absorption coefficient of the medium is increased. We found that the irradiance threshold after correction for the path length dependent absorption and scattering losses in the medium is lower due to the thermal pathway for the generation of seed electrons compared to the laser-induced optical breakdown. Furthermore, irradiance threshold gradually decreases with the increase in the absorption properties of the medium. Creating breakdown with lower irradiance threshold that is specific at the target chromophore can provide intrinsic target selectivity and improve safety and efficacy of skin treatment methods that use laser induced breakdown. Phys. 64(4), 1549-1554 (1976). 11. P. K. Kennedy, "A first-order model for computation of laser-induced breakdown thresholds in ocular and aqueous media. I. Theory," IEEE J. Quantum Electron. 31(12), 2241-2249 (1995). 12. D. X. Hammer, R. J. Thomas, G. D. Noojin, B. A. Rockwell, P. P. Kennedy, and W. P. Roach, "Experimental investigation of ultrashort pulse laser-induced breakdown thresholds in aqueous media," IEEE J. Quantum Electron. 32(4), 670-678 (1996). calculation of thresholds, absorption coefficients, and energy density," IEEE J. Quantum Electron. 35(8), 1156-1167 (1999

show abstract

“…Studies of the interaction of tightly focused femtosecond laser with water have revealed that this nonlinear energy absorption produces an excited plasma in the focal volume. The plasma expands supersonically into the surrounding tissue (the region of this supersonic expansion is referred to as the shock zone), and launches a pressure wave as the plasma expansion slows to acoustic velocity (Glezer et al, 1997;Juhasz et al, 1996;Vogel et al, 1996;Zysset et al, 1989). Ultimately, vaporized material at the focus forms a cavitation bubble, which expands outward and then collapses under external pressure (Juhasz et al, 1996;Vogel et al, 1996).…”

Section: Introduction/backgroundmentioning

confidence: 99%

“…However, the supersonic plasma expansion, the expansion of the cavitation bubble, as well as thermal diffusion all cause unwanted collateral damage to the surrounding tissue, limiting surgical precision (Juhasz et al, 1999;Noack et al, 1998;Vogel et al, 1999;Zysset et al, 1989). The size of the region affected by these mechanical (plasma and cavitation bubble expansion) and thermal effects increases as the amount of laser energy that is deposited into the sample increases.…”

Section: Introduction/backgroundmentioning

confidence: 99%

Using Femtosecond Laser Subcellular Surgery as a Tool to Study Cell Biology

Shen¹,

Colvin²,

Huser³

2007

View full text Add to dashboard Cite

Research on cellular function and regulation would be greatly advanced by new instrumentation using methods to alter cellular processes with spatial discrimination on the nanometer-scale. We present a novel technique for targeting submicrometersized organelles or other biologically important regions in living cells using femtosecond laser pulses. By tightly focusing these pulses beneath the cell membrane, we can vaporize cellular material inside the cell through nonlinear optical processes. This technique enables non-invasive manipulation of the physical structure of a cell with sub-micrometer resolution. We propose to study the role mitochondria play in cell proliferation and apoptosis. Our technique provides a unique tool for the study of cell biology.

show abstract

Time-resolved measurements of picosecond optical breakdown

Cited by 109 publications

References 19 publications

Time-resolved observations of shock waves and cavitation bubbles generated by femtosecond laser pulses in corneal tissue and water

Time-resolved observations of shock waves and cavitation bubbles generated by femtosecond laser pulses in corneal tissue and water

Influence of absorption induced thermal initiation pathway on irradiance threshold for laser induced breakdown

Using Femtosecond Laser Subcellular Surgery as a Tool to Study Cell Biology

Contact Info

Product

Resources

About