Transcript Lasers
Modern Optics PHY485F/1485F www.physics.utoronto.ca/~phy485/ModOpt/ Robin Marjoribanks McLennan Physics 1104C [email protected] What makes this course important? foundation course in modern (quantum) optics basic literacy in a modern, active area of physics fundamental science, concepts, understanding a subject of technology that supports many others an extremely active, intense area of current research numerous Nobel prizes in the last decade Topics laser as a pivot-point look backwards from invention to classical optics needed to understand how the laser tailors light, forward to the quantum optics explosion that has followed basic optics diffraction theory gaussian beams laser resonators semiclassical laser theory ultrafast pulse generation a selection of currently active research topics: laser cooling, photonic bandgap structures, extreme optics, quantum information and other topics The Laser Oscillator Laser oscillators are built in a Fabry-Perot resonator W. Silvfast http://cord.org/step_online/st1-5/st15ttl.htm solutions are standing waves in this laser cavity spectrum of possible frequencies satisfy: wn = n 2π c / L = n wo L is the cavity length c is speed of light these modes may each have their own amplitude En thus the optical field in the cavity can be written: En ei(nwot+f(n)) In a free cavity, with random f(n), we get ‘wild’ light. In a cavity where we make f(n)=0, we lock the modes together Ultrafast Ti:sapphire laser Kerr effect makes intense pulses ‘self-focus’ slightly intense pulses pass better through aperture, where weak ones blocked alters stability of cavity slightly, favoring intense pulses also can affect deflection of beam, to same effect modelocking can start from mechanical vibration: ‘magic modelocking’ Er-fiber laser output: 1550 nm 100 fs 2–40 mW pump: 980 nm diode 60 mW min fiber coupled modelocking: Kerr ellipserotation polarizer discrimination dispersion 2 kinds of fiber opposite GVD pump input coupler (WDM 980/ 1550nm ) optical pump (980nm diode laser) pigtail fiberoptic leads pigtail fiberoptic leads Er-doped fiber (5m length) pigtail fiberoptic leads polarization controller Faraday isolator/polarizer polarization controller pigtail fiberoptic leads pigtail fiberoptic leads output coupler Controller for thermoelectric cooler on pump partial recompression MetroCor fiber length electrical feedthroughs fiber optic feedthroughs Approach multiple resources textbook lectures online materials: demos, applications office hours other texts study/work groups all are needed each has particular advantages Lectures will concentrate on what lectures do best won’t just lead you through the textbook will provide interaction and feedback that books cannot will provide demonstrations and animations will depend on you having read also Textbook “Modern Optics and Lasers” course-notes by sign-up (please use index-cards) optional (cheap): “Introduction to Modern Optics” by Grant R. Fowles (get online errata correcting numerous errors) reference: “Optics” (4th edition), Hecht reference: “Lasers” by P.W. Milonni and J.H. Eberly (Wiley). Office Hours Professor Marjoribanks Wednesdays 2–3 pm (OK?) MP1104C marker to be determined Contact I’ll email using your official registered U of T email address (e.g., [email protected]) problem set corrections, class announcements, reminders may go there you’re responsible for email Problem sets Problem set due dates (posted on web) PS#1 - due 2 October PS#2 - due 18 October Midterm Test: 25 October 2007, 5-7 pm OK? PS#3 - due 15 November PS#4 - due 6 December (zero extensions) Group seminar presentations 1 December 10-5pm solutions posted on course web-site late policy: 20% off per day zero, once solutions are posted (~3 days) Marking scheme Term work: 4 problem sets (best 3 out of 4) seminar group presentation (1 Dec) term test 30% 10% 60% 100% Final exam final exam Course mark: 100% 60/40 flip-flop Midterm test – only impossibles 23 Monday 24 Tues 25 Wed 26 Thurs 27 Friday 9-10 10-11 xxxxx xxxxx 11-12 12-1pm 1-2 2-3 3-4 xxxxx xxxxx 4-5 √ 5-6 √ 1 3 3 3 6-7 1 1 2 3 2 7-8 1 1 1 1.5 1 1 1.5 1 8-9 Colloq