| 摘要 |
A laser system includes a multimode laser diode positioned at a range from a target. Backscatter from the target returns into the diode and to modify the emission. An induced modulation frequency in the emission effects oscillatory mode transitions to create an amplitude modulation in mode power for a selected mode, the mode being selected by an optical spectrum analyser or an interference filter. The diode is positioned initially for a minimum in the amplitude modulation, and readjusted by a selected increment in response to an incremental change in target position so as to reestablish the amplitude modulation to the minimum. The incremental change thereby equals the selected increment. |
