Technology Lecture: Orthogonally Polarised Lasers and Applications in Metrology
Date: 11 Feb 2009 - 11 Feb 2009
Venue: SIMTech Auditorium, Tower Block, Level 3
The objective of this technology lecture is to raise awareness of new developments in the advanced laser-based dimensional metrology technology and applications. Participants will gain a broader understanding of laser measuring techniques pertinent to research and development of high precision dimensional measurements.
A high-resolution displacement sensor based on multiple feedback effect of birefringence dual frequency lasers will be presented. When the system operates in very strong feedback regime with asymmetric feedback induced by the inclined external feedback reflector in an orthogonal polarised dual frequency laser, the modulation frequency of the laser intensity is seven times higher than that of the conventional optical feedback system, due to multiple feedback effect. A fringe shift will correspond to a displacement of a fourteenth wavelength of the external reflector. The intensity transferring periodically between the two frequencies has been examined. A period of intensity transfer can be divided into four states, namely o-light, o-light and e-light, e-light, and no light, and each polarisation state corresponds to λ/56 displacement of the external reflector. According to the appearing sequence of the four states, the movement direction of external reflector can be discriminated. Significantly, a novel displacement sensor with a resolution of being as high as 11.3nm with the function of direction discrimination is achievable.
About the Speaker
Prof. Zhang Shulian is the Director of the State Key Lab of Precision Measurement Technology & Instruments, Department of Precision Instruments, Tsuinghua University, Beijing. A former Director of Optic-electrical Engineering Institute of Tsinghua University, Prof. Zhang has done extensive research on laser technology and dimensional metrology for more than 30 years. He holds 42 patents and is the author of 5 books with over 200 academic papers published in this field.
Prof. Zhang is the recipient of many national research awards, including the Second class award of the National Science and Technology pertaining to "Orthogonally polarised lasers and based-on precision instruments” in 2007; the First class Award of Science and Technology Award of National Ministry of Education for his research in Tuning characteristics of two/three mirror lasers, 2006; the Second Class Science and Technology Award developing “Two polarisation frequency competition displacement sensing laser system” in 2000; the First Class Science and Technology Award in recognition of his research in “Laser frequency splitting phenomenon and application in metrology” in 1994; and the Second Class National Science and Technology Award for developing “Four Frequency ring laser and angle measurement technology”, 1985.
His current research interests encompass orthogonal polarisation lasers and application in metrology, nano measurement, optical grating sensing, etc.
9.45am : Registration
10.00am: Presentation by Prof Zhang
(please click A, B, C ro view the presentation slides)
11.15am : Refreshment & Networking
Who Should Attend
Senior management staff, R&D managers, engineers, academic staff, researchers and students.
Pre-registration for the lecture is free of charge.
For technical enquiries, please contact Dr Fang Zhongping, Senior Scientist, SIMTech Precision Measurements Group
Email: zpfang@SIMTech.a-star.edu.sg; Tel: 67938269
For registration and event details:
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