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 characteristics of a Nd:YVO4 laser pumped by a laser diode modulated at high frequency. We have investigated noise characteristics of a Nd:YVO4 laser pumped by a laser diode that is oscillating in a stable multilongitudinal mode because of modulation by a high-frequency (several hundred megahertz) current. As a result, low-noise operations of -130 dB/Hz above frequencies of 1 MHz have been achieved. This noise level is comparable to the level obtained when pumping a Nd:YVO4 laser with a laser diode that is oscillating in a single longitudinal mode. However, a noise peak corresponding to relaxation oscillations of the Nd:YVO4 laser has appeared around a frequency of several hundred kilohertz.