Marc Nantel

The effects of degraded spatial coherence on ultrafast-laser channel etching.

When laser-etching channels through solid targets, the etch-rate is known to decrease with increasing depth, partly because of absorption at the sides of the channel. For ultrafast-laser pulses at repetition rates >100 MHz, we show that the etch-rate is also affected by optical properties of the beam: the channel acts as a waveguide, and so the pulses will decompose into dispersive normal modes. Additionally, plasma on the inner surface of the channel will cause scattering of the beam. These effects will cause a loss of spatial coherence in the pulse, which will affect the propagated intensity distribution and ultimately the etch-rate. We have characterized this effect for various foil thicknesses to determine the evolution of the beam while drilling through metal.

Photonics education and training in Ontario, Canada: an integrated plan

Canada has established itself as a leader in photonics. Ontario in particular - home of giants such as JDS Uniphase, Nortel Networks, GSI Lumonics and an increasing number of successful start-up companies - has seen the demand for highly-qualified personnel in photonics grow exponentially in the past few years. The scarcity of these photonics experts has become - recent market woes not withstanding - the single most important impediment to the further growth of photonics companies. Nonetheless, it is mostly at the graduate school level that lasers and photonics are introduced to students, with only very few thus being trained in the field. Photonics Research Ontario has put together an aggressive plan to change this situation and present Optics, Lasers and Photonics at all levels in the education system, from grade school to graduate school. This paper will present this Photonics Education and Training plan, as well as other efforts being undertaken across Canada to address this crucial issue. The paper will focus especially on the training of Photonics Technicians and Technologists in Ontarios Community Colleges. The new curriculum designed for these programs will be presented, and the importance of industry support will be emphasized.

Transverse coherence measurement using a folded Michelson interferometer

The transverse coherence of a 1 ps pulsed laser beam was measured using a technique involving a modified Michelson interferometer and separate reference images. Using this technique, the transverse coherence of a selected plane in the laser beam was determined, in this case at the exit of a channel in a metal foil self-drilled by the laser. Images of each arm were used as references. Through this technique, it is possible to use the interference patterns produced with uneven intensity distributions and for pulsed lasers on a single-shot basis. The results of these measurements were then shown to be in agreement with those obtained using a Youngs double-slit setup.

Optical coherence and beamspread in ultrafast-laser pulsetrain-burst hole drilling

Pulsetrain-burst machining has been shown to have advantages over single-pulse laser processing of materials and biological tissues. Ultrafast lasers are often able to drill holes in brittle and other difficult materials without cracking or swelling the target material, as is sometimes the case for nanosecond-pulse ablation; further, pulsetrain-bursts of ultrafast pulses are able to recondition the material during processing for instance, making brittle materials more ductile and striking advantages can result. In the work we report, we have investigated hole-drilling characteristics in metal and glass, using a Nd:glass pulsetrain-burst laser (1054 nm) delivering 1-10 ps pulses at 133 MHz, with trains 3-15 μs long. We show that as the beam propagates down the channel being drilled, the beam loses transverse coherence, and that this affects the etch-rate and characteristics of channel shape: as the original Gaussian beam travels into the channel, new boundary conditions are imposed on the propagating beam principally the boundary conditions of a cylindrical channel, and also the effects of plasma generated at the walls as the aluminum is ablated. As a result, the beam will decompose over the dispersive waveguide modes, and this will affect the transverse coherence of the beam as it propagates, ultimately limiting the maximum depth that laser-etching can reach. To measure transverse beam coherence, we use a Youngs two-slit interference setup. By measuring the fringe visibility for various slit separations, we can extract the transverse coherence as a function of displacement across the beam. However, this requires many data runs for different slit separations. Our solution to this problem is a novel approach to transverse coherence measurements: a modified Michelson interferometer. Flipping the beam left-right on one arm, we can interfere the beam with its own mirror-image and characterise the transverse coherence across the beam in a single shot.

Three new bachelors of photonics in Ontario

After the introduction in 2001 of community college programs at the Photonics Technician/Technologist levels, the need to cover the photonics educational space at the undergraduate level was addressed. In the last year, three very different new undergraduate degrees in photonics have started to develop in Ontario. These programs are presented in this paper. The Honours B.Sc. in Photonics at Wilfrid Laurier University (Waterloo) will develop a strong understanding of the theory and application of photonics, with practical hands-on exposure to optics, fibre optics, and lasers. This program benefits from the particularity that the department offering it combines both Physics and Computer Science. At McMaster University, the Engineering Physics program will provide students with a broad background in basic Engineering, Mathematics, Electronics, and Semiconductors, as well as an opportunity to pursue Photonics in greater depth and to have that fact recognized in the program designation. The Niagara and Algonquin College Bachelor of Applied Technology in Photonics program is co-op and joint between the two institutions. Emphasis is placed on the applied aspects of the field, with the more hands-on experimental learning taking precedence in the first years and the more advanced theoretical subjects following in the latter years.

Ten years of photonics education at the college level in Ontario: Results and by-products

In 2000, there was no way for an Ontario student to obtain a credential in optics, laser or photonics without going through graduate school. This was in, arguably, the world-leading jurisdiction in photonics-enabled telecommunications industry. To alleviate this problem and supply the job market with highly-qualified people in the field of optics and photonics, the Ontario Centres of Excellence - then as Photonics Research Ontario - partnered with Algonquin College (Ottawa) and Niagara College (Welland) to establish over the past decade a suite of programs: a 1-year Certificate in Advanced Lasers, a 2-year Diploma for Photonics Engineering Technician, a 3-year Diploma for Photonics Engineering Technologists and a 4-year Bachelor of Applied Technology - Photonics. Much has been learnt along the way - the crucial need for industrial partner and government support, for example - and many course corrections had to be made (telecom bust, anyone?). The author will share the results of this 10-year journey so far, the lessons learnt, and a view to the next ten years for these programs and photonics education in Ontario in general.

Undergraduate degrees in photonics in Ontario, Canada

In the last year, three very different new undergraduate degrees in photonics have started to develop in Ontario where none was available before. One is an Honours B.Sc. in Photonics, one is a Photonics Engineering degree and another is a Bachelor of Applied Technology in Photonics. This paper presents these programs.

Photonics education and training in ontario community colleges

Ontario, Canada, is home to world giants and multiple start-up companies in photonics, yet these companies are having problems finding enough highly-qualified personnel with a background in optics, lasers and photonics to sustain their long-term growth. Photonics Research Ontario, in collaboration with Niagara College and Algonquin College, is establishing new programmes for training technicians and technologists in photonics. In this paper, the new curricula will be presented and the importance of a solid industry support will be emphasized. More information can be obtained on the project’s webpage at .Ontario, Canada, is home to world giants and multiple start-up companies in photonics, yet these companies are having problems finding enough highly-qualified personnel with a background in optics, lasers and photonics to sustain their long-term growth. Photonics Research Ontario, in collaboration with Niagara College and Algonquin College, is establishing new programmes for training technicians and technologists in photonics. In this paper, the new curricula will be presented and the importance of a solid industry support will be emphasized. More information can be obtained on the project’s webpage at .