Abstract
We present a novel scheme to realize the direct real-time measurement of liquid evaporation rate and nanometer order liquid level monitoring. It is based on the phase measurement technology of Nd:YAG microchip laser frequency-shifted feedback, which not only has a high resolution and precision but also ultrahigh sensitivity. The evaporation rates of four different transparent liquids and hot water are measured. Experimental results indicate the ease and convenience of measuring and present promising application prospects in non-cooperative target measurement.