NOISE CHARACTERISTICS OF A NDYVO4 LASER-PUMPED BY LASER-DIODE MODULATED AT HIGH-FREQUENCY

We report, for the first time to our knowledge, on the noise character istics of a Nd:YVO4 laser pumped by a laser diode modulated at high fr equency. We have investigated noise characteristics of a Nd:YVO4 laser pumped by a laser diode that is oscillating in a stable multilongitud inal mode because of modulation by a high-frequency (several hundred m egahertz) current. As a result, low-noise operations of -130 dB/Hz abo ve frequencies of 1 MHz have been achieved. This noise level is compar able to the level obtained when pumping a Nd:YVO4 laser with a laser d iode that is oscillating in a single longitudinal mode. However, a noi se peak corresponding to relaxation oscillations of the Nd:YVO4 laser has appeared around a frequency of several hundred kilohertz.