It often takes one single event to interest teenagers in a topic that will become a passion or a career. It is in this spirit that
the SPIE and OSA Student Chapters at Université Laval created the Photonic Games three years ago, to kindle an
interest in teenagers towards studies and careers in optics. The activity, offered each year to more than a hundred grade
11 students, is divided in two parts. First, we offer a hands-on workshop in their classrooms about reflection, refraction,
dispersion, birefringence and polarization. A few days later, all the students come to the <i>Centre d'optique, photonique et
laser</i> (COPL) at Université Laval for a day of competition where a volunteer physics student accompanies each team of
four students. Challenges are various to promote the qualities that make great scientists: creativity, teamwork,
knowledge, inquisitiveness, self-confidence and perseverance. The first two editions of the Photonic Games have proven
to be beneficial for the students, teachers and volunteers, and we endeavor to improve it as we construct on our
experience with the past editions to fine-tune and improve the Photonic Games concept.
Using the vectorial diffraction theory established by Richards and Wolf, we demonstrate that the resolution of a two-photon microscope can be improved with a radially polarized TM<sub>01</sub> laser beam and an interface between dielectrics, instead of the linearly polarized Gaussian beam already used in laser scanning microscopy. To verify the theoretical results, we developed a mode converter producing radially polarized beams and we have integrated it in a commercial two-photon microscope.
We present two optical systems that can transform a Gaussian beam into the lowest-order transverse magnetic laser
beam (the so-called TM<sub>01</sub> laser beam). When a TM<sub>01</sub> laser beam is focused by an objective with a high numerical aperture (NA > 0.9), theory predicts the appearance of a bright central feature at focus; the width of this feature is
smaller than that of the focal spot obtained with a Gaussian beam [1,2]. Our goal is to improve the lateral resolution of
two-photon microscopy when a TM<sub>01</sub> laser beam is used.