Opto-mechatronic response of high-performance force-sensing microlasers

摘要

The frequency response of force-measuring microlaser sensors (Nd:YAG) is tested in a special opto-mechatronic test setup. In this setup a piezo translator/frame configuration generates sinusoidal forces in the range from DC up to 100 kHz and higher. The force amplitude covers a range of approximately eight decades (1N- 10 nN). Amplitude and phase response of the test setup including the laser sensor under test are measured. Because of the frequency-analogue output signal of the laser sensor, dynamic frequency measurements based on frequency/period counting, Bessel spectrum analyzing and FM-demodulation have to be performed. To conclude on the dynamic response of the microlaser itself the mechanical part of the test setup and the laser sensor is modeled mathematically. The theoretical response of the test setup is in good agreement with its measured frequency response, which means that modeling of the force-to-frequency conversion by the laser sensor is realistic. Based on static and dynamic measurement data, we conclude an excellent proportional response of the laser sensor for modulation frequencies up to 100 kHz. In this frequency range, the characteristics of the force-to-frequency conversion are strictly linear over approximately nine decades.