| 摘要 |
PURPOSE:To carry out analysis in a stable condition by a method wherein a semiconductor is used for light source, the driving power is modulated to modulate luminous intensity, and an electric signal synchronized with a phase of a modulation signal of the driving power and generated by a sample optical sound effect is recorded. CONSTITUTION:A light radiated from a light source 1 is modulated by modulating a driving power of the light source 1 with a signal of a modulating frequency oscillator 16. A modulated light from the light source 1 is applied to a sample in an optical sound cell 6 through a condensing lens 5. An optical sound effect arising on the sample is detected on a microphone in the optical sound cell and outputted as an electric signal. The electric output is amplified through a preamplifier 7, locked in through a lock-in amplifier 8, a phase detection is carried out between it and a modulation frequency of the light source oscillated from the frequency oscillator 16, an electric signal synchronized with the modulation frequency of the light source is outputted into a recorder 9, and thus an optical sound spectrum of the measured sample is recorded. |
