2018 BFY III Abstract Detail Page

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Abstract Title: W26: Speed of light using a pulsed diode laser
Abstract: This workshop explores a speed-of-light experiment suitable for introductory or intermediate level students to learn experimental basics (apparatus alignment, use of coaxial cables & oscilloscope, error propagation, systematic effects) yet which is easily expanded into an advanced experiment, in which students construct the electro-optical system themselves and examine laser diode non-linearity, impedance matching, and different methods of analysis.  Participants will work through most of these aspects, as time allows.
The experimental concept is straightforward: a light pulse travels from a diode laser to a distant mirror and back to a detector; timing is done with a digital oscilloscope.  Taking measurements at different mirror distances allows for elimination of electronic delays.  Precision & accuracy are under 2% for mirror at 6 meters, even better if longer distances can be arranged.  
The laser-detector system is easily assembled from commercially available parts (or save cost by making your own mounting mechanics).  A moderately fast pulse generator and digital oscilloscope are needed to drive & measure the laser pulse.
Abstract Type: Workshop

Author/Organizer Information

Primary Contact: Timothy Roach
College of the Holy Cross
1 College St
Worcester, MA 01610

Workshop Documents

Workshop Doc 1: Download the Workshop Doc 1
Workshop Doc 2: Download the Workshop Doc 2
Workshop Doc 3: Download the Workshop Doc 3