PROBLEM TO BE SOLVED: To provide an apparatus to highly accurately measure a constituent concentration of an object to be measured with a small number of measurement items while achieving reduction in a measurement time.SOLUTION: Laser diodes 1-1 and 1-2 modulate intensity of light of two waves with different wavelengths by the same frequency and by signals of different phases, and irradiate an object 11 to be measured with the light. An acoustic sensor 6 detects a photoacoustic signal generated from an object 11 to be measured by a photoacoustic effect, and coverts it to an electric signal proportional to acoustic pressure. An information processing device 10 changes the power of light emitted from the laser diode 1-2, measures the power of light and the intensity of an electric signal output from a lock-in amplifier 9, approximates the relationship between the intensity of the electric signal and the power of light by a numerical expression, estimates the power of light at a true point where the intensity of the electric signal reaches a minimum level based on the result of the approximation, and derives a constituent concentration of an object to be measured contained in the object 11 to be measured based on the result of the estimation.SELECTED DRAWING: Figure 1COPYRIGHT: (C)2016,JPO&INPIT【課題】少ない測定点数で測定対象の成分の濃度を高い精度で求め、測定時間を短縮する装置を提供する。【解決手段】レーザダイオード1-1,1-2は、異なる波長の2波の光を同一周波数で且つ異なる位相の信号により強度変調して被測定物11に照射する。音響センサ6は、光音響効果によって被測定物11から発生する光音響信号を検出し、音圧に比例した電気信号に変換する。情報処理装置10は、レーザダイオード1-2から放射される光のパワーを変化させて、光のパワーとロックインアンプ9から出力される電気信号の強度とを測定し、電気信号の強度と光のパワーとの関係を数式で近似し、近似の結果に基づいて電気信号の強度が最低となる真の点における光のパワーを推定し、推定の結果に基づいて被測定物11に含まれる測定対象の成分の濃度を導出する。【選択図】図1
