Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Thomas Young (scientist) wikipedia , lookup
Photonic laser thruster wikipedia , lookup
Ultraviolet–visible spectroscopy wikipedia , lookup
3D optical data storage wikipedia , lookup
Ultrafast laser spectroscopy wikipedia , lookup
Nonlinear optics wikipedia , lookup
Experimental Techniques of Optics Spring 2015 University of New Mexico PHYC 476,477, 302L http://www.optics.unm.edu/sbahae/Optics Lab/ Pre-requisites: 302L: PHYC 302 or 330 or 262 or 160 476L/477L: PHYC 302 or PHYC/ECE 463 or 464 Please drop the course if you have not passed at least one of the pre-requisite courses. Instructor: Mansoor Sheik-Bahae Teaching Assistants: Mohammad Ghasemkhani and Nathan Giannini Lab Coordinator: Dr. Michael Hasselbeck Grading Policy • Attendance, Interaction with TAs and Instructors during the lab sessions • Lab Reports • Student Seminars (?) • Oral Exam? Lab Safety First All students enrolled are required to read the above OSHA manual carefully. You will be asked to sign an "agreement of understanding" form on the first session of this course. Experiments • Basic Optics Experiments (for 302L only) • The Wavemeter • Velocity Measurements by Optical Techniques • Ray Tracing and Lens Aberrations • Fiberoptics • • • • • • • Modelocking a CW Laser Fourier Optics Polarization Study He-Ne Laser Diode-Pumped Solid-State (DPSS) Laser Holography Nonlinear Optics (NEW; being developed) Error Analysis (how many significant figures?) Is c=299 792 458 m/s exact? • A measurement is not meaningful without an error estimate (uncertainty) • No measurement is ever exact • “Error” does NOT mean “blunder” or “mistake” (the latters can be corrected for) “It is better to be roughly right than precisely wrong!” Alan Greenspan Former U.S. Federal Reserve Chairman Types of Error • Statistical (Random) Errors: Results from a random fluctuation in the process of measurement. Often quantifiable in terms of “number of measurements or trials”. Tends to make measurements less precise. • Systematic Errors (Blunders?): Is this systematic error? Results from a bias in the observation due to observing conditions or apparatus or technique or analysis. Tend to make measurements less accurate. • Instrument Limitation Error: 12.650.005 Any measuring device can be used to within a degree of finesse. half of “least count” Measurement Histogram Measurement Uncertainty xm=xave xave (N-1) Error Propagation • If the parameter of interest f = F(x, y, z, …) depends on multiple measured parameters x, y, z, …. • The error in f, f, depends on the function F, measured parameters x, y, z, …, and their errors, x, y, z, …: 2 2 2 F 2 F 2 F 2 f x y z ... x z y Errors from independent (un-correlated) parameters add in quadrature. An Example: Determine peak on-axis intensity of a pulsed laser beam: I (W / cm 2 ) E ( joules ) E K t p (sec) A( cm 2 ) t p w2 K is a constant I ( measured ) I ave I with I ave K Eave 2 t p ave wave and E 2 1 2 2 t 2 2 E 2 w 2 I K E p t w2 t 2 w2 t 2 w3 p ave p ave p ave • energy meter 2 or • beam profiler (calibration?) For instance: E=(5.2±0.05) mJ I 0.1 I ave 2 2 I E t p w 2 I E t p w • fast photo-diode and scope input impendence? w=(120±2) µm I (measured)=2.1 ±0.2 GW/cm2 tp=(11±1) ns Data Fitting (comparing with theory) “least squares” analysis Minimize 2 For linear fit (or power laws in log-log plots): Graphics or data analysis softwares (Origin, Excel, ..) do this for you. 2 0 m 2 0 b weighted Keep the lab and the equipment clean & organized Absolutely no finger prints on optics please!!