Laser light source apparatus, and method for controlling temperature of wavelength conversion element in laser light source apparatus

摘要

The wavelength of fundamental wave light emitted from a semiconductor laser is converted by a wavelength conversion element, and the wavelength-converted light is emitted. A power supply circuit feeds electric power to the semiconductor laser. A control part controls an amount of electric power to be fed to a heater such that the wavelength conversion element becomes a temperature that optimizes the wavelength conversion efficiency. Temperatures detected by an element temperature detector and a light source part temperature detector are introduced to the control part, and the control part takes a wavelength conversion element temperature, at which a temperature detected by the light source part temperature detector is minimum, as a set temperature that makes the wavelength conversion efficiency optimal, and feedback-controls the wavelength conversion element temperature such that the wavelength conversion element temperature is at the set temperature by controlling the heating quantity of the heater.

主权项

1. A laser light source apparatus comprising:
a light source part having a semiconductor laser, a wavelength conversion element configured to convert a wavelength of a laser beam emitted from the semiconductor laser, and an external resonator configured to select that laser beam which has a prescribed wavelength from the laser beam released from the wavelength conversion element and reflect the selected laser beam toward the semiconductor laser; a power supply circuit configured to feed electric power to the semiconductor laser; an element temperature detecting unit configured to detect temperature of the wavelength conversion element; a heating unit configured to heat the wavelength conversion element; a control part configured to control the power supply circuit; a light source part temperature detecting unit configured to detect temperature of the light source part, the temperature of the light source part not including the temperature of the wavelength conversion element; an optimal temperature setting unit configured to, when the wavelength conversion element is irradiated with the laser beam, configured to measure a plurality of light source part temperatures with the light source part temperature detecting unit, configure to measure a plurality of wavelength conversion element temperature with the element temperature detecting unit in connection with said plurality of light source part temperature, configured to select lowest light source part temperature from said plurality of light source part temperatures, configured to find wavelength conversion element temperature corresponding to the lowest light source part temperature, and configured to take the wavelength conversion element temperature corresponding to the lowest light source part temperature as an optimal temperature of the wavelength conversion element; and a temperature controller configured to control an amount of electric power to be supplied to the heating unit based on a difference between the temperature of the wavelength conversion element detected by the element temperature detecting unit and the optimal temperature such that the temperature of the wavelength conversion element becomes the optimal temperature.