Patent ID: 11921040
Assignee: SHIMADZU CORPORATION
Field: Measurement (Instruments)
Classification: CPC G  H | IPC G

Claim 0:
1. A gas absorption spectroscopic measurement device configured to acquire a component concentration of a gas to be measured by cavity ring-down absorption spectroscopy, the gas absorption spectroscopic measurement device comprising:
a laser irradiation unit;
an optical resonator configured to cause light emitted from the laser irradiation unit to resonate, the optical resonator including a measurement cell for accommodating the gas to be measured; and
a first detector configured to detect light taken out of the optical resonator,
wherein the laser irradiation unit includes:
a frequency adjustable laser light source;
a frequency converter configured to selectively output either laser light having the same frequency as the laser light source or laser light having a frequency of the frequency of the laser light source multiplied by a predetermined number of times;
a frequency modulator configured to modulate the frequency of the laser light emitted from the frequency converter using a modulation signal;
a second detector configured to detect returning light from the optical resonator derived from the laser light emitted to the optical resonator after being modulated by the frequency modulator; and
a feedback controller configured to generate an error signal affected by a difference between a frequency of the laser light emitted to the optical resonator and a mode frequency of the optical resonator, based on a detection signal from the second detector and the modulation signal, thereby controlling an oscillation frequency of the laser light source in response to the error signal.