Femtosecond Laser Ablation and Micromachining
In recent years femtosecond laser ablation and micromachining has been an emerging area, offering new opportunities for materials processing due to the qualitatively different interactions of ultrashort light pulses with solids. The work in our laboratory on femtosecond laser – materials interactions covers a broad range, directed both at fundamental studies as well as applications. The ultrafast laser pulses can be utilized to modify materials on the nanometer or micron length scales, and undertake precision laser machining. In these projects, we work closely with the Canadian Centre for Electron Microscopy (CCEM) within the Brockhouse Institute for Materials Research. The capabilities of the CCEM enable detailed studies of the final state of laser-modified targets through a host of capabilities including transmission electron microscopy, scanning probe microscopy, focused ion beam techniques, high-resolution optical microscopy, and scanning electron microscopy. Our more recent research activities in this area have concentrated on potential applications in silicon photonics, and investigations of ripple formation at the buried interface in silicon dioxide/silicon samples.
Electron Microscopic Studies of Ytterbium-Doped Optical Fibres
We have initiated a project involving the ultrahigh resolution electron microscopy of ytterbium-doped optical fibres. Doped fibres represent a very important domain in terms of state-of-the-art laser and optical amplifier technology. One of the key motivations for initiating the work was to gain further insights into photodarkening mechanisms in doped optical fibres. The ultrahigh resolution electron microscopy of Yb atoms in glass, conducted with the facilities of the Canadian Centre for Electron Microscopy, is extremely challenging experimentally. We aim to detect single Yb atoms in glass which can reveal effects of ion clustering. The tour-de-force experiments push the techniques of sample preparation and analysis to the limit. Beyond possible insights into photodarkening, our experiments could also lead to new knowledge into fabrication mechanisms of various specialty optical fibres.
Applications of THz Radiation
The application of THz radiation is a rapidly developing area of R&D worldwide, both in wide-ranging interdisciplinary applications as well as in fundamental science. Ultrafast THz radiation capabilities have been established in our laboratory based on nonlinear optical conversion and electro-optical detection using near-visible femtosecond light pulses from our Ti:sapphire laser systems. The ultrafast pulse capability enables pump-probe experiments whereby the properties of a material can be altered on an ultrashort time frame and the recovery of the target can be monitored as a function of time. We have used these capabilities for selected experiments including the determination of nonlinear optical coefficients for selected semiconductors, and the study of carrier relaxation in optically-excited ion-irradiated silicon. Our group was also part of the initiative to establish high intensity THz capabilities at the Advanced Laser Light Source (ALLS) at INRS in Montreal.
Selected Publications in the Above Research Areas
Ran An, Ghadeer W. Khadar, Emilia I. Wilk, Brent Emigh, Harold K. Haugen, Gregory R. Wohl, Brett Dunlop, Mehran Anvari, Joseph E. Hayward, and Qiyin Fang, “Ultrafast laser ablation and machining large-size structures on porcine bone”, Journal of Biomedical Optics, 18, 070504 (2013)
B. Emigh, R. An, E.M. Hsu, T.H.R. Crawford, H.K. Haugen, G.R. Wohl, J.E. Hayward, and Qiyin Fang, “Porcine cortical bone ablation by ultrashort pulsed laser irradiation”, Journal of Biomedical Optics, 17, 028001 (2012)
E.M. Hsu, N.A. Mailman, G.A. Botton, and H.K. Haugen, “Microscopic investigation of single crystal diamond following ultrafast laser irradiation”, Appl. Phys. A, 103, 185 (2011)
F. Blanchard, G. Sharma, L. Razzari, X. Ropagnol, H.-C. Bandulet, F. Vidal, R. Morandotti, J.-C. Kieffer, T. Ozaki, H. Tiedje, H. Haugen, M. Reid, and F. Hegmann, “Generation of Intense Terahertz Radiation via Optical Methods”, invited review paper, IEEE JSTQE 17, 5 (2011)
H.F. Tiedje, D. Saeedkia, M. Nagel, and H.K. Haugen, “Optical Scanning Techniques for Characterization of Terahertz Photoconductive Antenna Arrays”, IEEE Transactions on Microwave Theory and Techniques, Special Issue on THz Technology, 58, 2040 (2010)
M. Budiman, E.M. Hsu, H.K. Haugen, and G.A. Botton, “Cross-sectional study of femtosecond laser bulk modification of crystalline α-quartz”, Appl. Phys. A, 98, 849 (2010)
T.H.R. Crawford, G.A. Botton, H.K. Haugen, “Crystalline orientation effects on conical structure formation in femtosecond laser irradiation of silicon and germanium”, Appl. Surf. Sci., 256, 1749 (2010)
C.L. Armstrong, E.M. Hsu, H.F. Tiedje, and H.K. Haugen, “Selected Applications of Ultrafast Terahertz Spectroscopy”, Physics in Canada, 65, 121 (2009)
J. Bonse, A. Rosenfeld, C. Grebing, G. Steinmeyer, N. Mailman, G.A. Botton, and H.K. Haugen, “Ablation and structural changes induced in InP surfaces by single 10-fs laser pulses in air”, J. Appl. Phys, 106, 074907 (2009)
H.M. Hsu, T.H.R. Crawford, C. Maunders, G.A. Botton, H.K. Haugen, “Cross-sectional study of periodic structures on gallium phosphide induced by ultrashort laser pulse irradiation”, Appl. Phys. Lett. 92, 221112 (2008)
T.H.R. Crawford, J. Yamanaka, E.M. Hsu, G.A. Botton, H.K. Haugen, “Femtosecond laser irradiation of metal and thermal oxide layers on silicon : studies utilizing cross-sectional transmission electron microscopy”, Appl. Phys. A, 91, 473 (2008)
T. H. R. Crawford, J. Yamanaka, G. A. Botton, H. K. Haugen, “High-resolution observations of an amorphous layer and sub-surface damage formed by femtosecond laser irradiation of silicon”, J. Appl. Phys. 103, 053104 (2008)
A. Weck, T. H. R. Crawford, D. S. Wilkinson, H. K. Haugen, J. S. Preston, “Laser drilling of high aspect ratio holes in copper with femtosecond, picosecond, and nanosecond pulses”, Appl. Phys. A 90, 537 (2008)
F. Blanchard, L. Razzari, H.-C. Bandulet, G. Sharma, R. Morandotti, J.-C. Kieffer, T. Ozaki, M. Reid, H. F. Tiedje, H. K. Haugen, and F. A. Hegmann, “Generation of 1.5 micro-Joule single-cycle terahertz pulses by optical rectification from a large aperture ZnTe crystal”, Optics Express 15, 13212 (2007)