TUNABLE REPETITION RATE OPTICAL SPECTROSCOPY WITH HIGH-POWER VISIBLE DIODE-LASERS

The methodology and apparatus are described to perform tunable repetit ion rate optical spectroscopic measurements using high-power visible d iode lasers. Here, a train of picosecond pulses interrogates a materia l, a sample, or a device under test. The response of the sample or dev ice varies as the pulse repetition frequency changes. Using an rf modu lated high-power AlGaInP 670-nm diode laser, the pulse train repetitio n frequency may be smoothly varied from the kHz range up to the GHz ra nge. The power and the pulse width may be kept constant by adjusting t he rf power and the dc injection current. This procedure is automated through computer control. Here we describe the details of our particul ar setup and present examples of the technique.