Schematic of diagram
(Click figure to enlarge)
Position vs phase delay
(Click figure to enlarge)
Note: oscilloscope not included
Features
Compact design
Phase method with high accuracy
Refractive index measurement
Optional media tube
Introduction
This experimental system is designed to measure the speed of light in air/media using the well-known phase method. It employs a 100 MHz intensity-modulated optical beam. By measuring the corresponding phase delay of a mixed optical signal at 455 kHz from a corner reflector, placed at various locations on a rail of 60 cm in length, the speed of light can be precisely determined within 5% accuracy by means of curve-fitting.
In addition, it can be expanded to measure the refractive index of various media such as organic glass, synthetic quartz, and liquid by using an optional media tube.
The instruction manual contains comprehensive materials including experimental configurations, principle and step-by-step instructions. Please click Experiment Theoryand Contents to find more information about this apparatus.
Specifications
| Description | Specifications |
| Light Source | Semiconductor Laser<3 mW @ 650 nm |
| Length of Rail | 0.6 m |
| Signal Modulation Frequency | 100 MHz |
| Phase Measurement Frequency | 455 kHz |
| Length of Round-Trip Optical Path | 0 ~ 1.0 m (retroreflector travel 0 ~ 0.5 m) |
| Measurement Error of Speed of Light | 5% or better |
Part List
| Description | Qty |
| Main Unit | 1 |
| BNC Cable | 2 |
| Manual | 1 |
| Transparent Liquid Tube with Support Carriers | optional |
Schematic of diagram
(Click figure to enlarge)
Position vs phase delay
(Click figure to enlarge)
